          United States Court of Appeals
                      For the First Circuit

No. 19-1150
                    ALEJANDRO A. DÍAZ-ALARCÓN,

                      Petitioner, Appellant,

                                v.

                   MICHELLE S. FLÁNDEZ-MARCEL,

                      Respondent, Appellee.



          APPEAL FROM THE UNITED STATES DISTRICT COURT
                 FOR THE DISTRICT OF PUERTO RICO

       [Hon. Carmen Consuelo Cerezo, U.S. District Judge]


                              Before

                  Thompson, Kayatta, and Barron,
                          Circuit Judges.



     Maricarmen Carrillo-Justiniano for appellant.
     Steven P. Lausell Recurt, with whom Rafael E. Rodríguez Rivera
and Legal Aid Clinic, Community Law Office, Inc., Inter-American
University of Puerto Rico were on brief, for appellee.



                        November 27, 2019
            THOMPSON, Circuit Judge.         It is not every day that a

child-custody fight ends up in federal court.               But here we are.

Invoking the Hague Convention on the Civil Aspects of International

Child Abduction ("Convention"), see Oct. 25, 1980, T.I.A.S. No.

11,670, 1343 U.N.T.S. 89, reprinted in 51 Fed. Reg. 10494-01 (Mar.

26, 1986), and its implementing statute, the International Child

Abduction    Remedies    Act    ("ICARA"),   see   22    U.S.C.   §§    9001-11,

Alejandro Díaz-Alarcón seeks return of his daughter from the United

States to Chile. To protect her privacy, we will call the daughter

"ADF."    Opposing Díaz-Alarcón is ADF's mother, Michelle Flández-

Marcel.   A federal district judge denied Díaz-Alarcón's petition.

He appeals.       We affirm.

                               Setting the Stage

                                 Legal Basics

            Over one hundred countries — including the United States

and Chile — are contracting parties to the Convention.                 See Status

Table,    HCCH,     https://www.hcch.net/en/instruments/conventions/status-

table/?cid=24 (last visited Nov. 26, 2019).             Broadly speaking, the

Convention aims to deter parents from abducting their children to

a country whose courts might side with them in a custody battle.

See Darín v. Olivero-Huffman, 746 F.3d 1, 7 (1st Cir. 2014); see

generally Mozes v. Mozes, 239 F.3d 1067, 1069 (9th Cir. 2001)

(noting     that    "[d]espite    the   image   conjured     by   words     like

                                     - 2 -
'abduction' and 'force,' the Convention was not drafted in response

to any concern about violent kidnappings by strangers" — instead,

"[i]t was aimed . . . at the unilateral removal or retention of

children by parents, guardians or close family members" (some

quotation marks omitted)).1           A federal statute — ICARA — implements

the Convention by (among other things) allowing a                     parent to

petition a federal or state court to return an abducted child to

the   child's        country   of   habitual    residence.      See   22   U.S.C.

§ 9003(b).         To prevail, the party seeking relief must establish by

a preponderance of the evidence that the abductor "wrongfully

removed       or   retained    [the   child]    within   the   meaning     of   the

Convention."2        Id. § 9003(e)(1).

               A petition-receiving court may not decide who should

have custody, however.          See Darín, 746 F.3d at 8; see also Walsh

v. Walsh, 221 F.3d 204, 218 (1st Cir. 2000) (noting that because

"[c]ourts are not to engage in a custody determination," it matters

not "who is the better parent in the long run") (second quotation

quoting Núñez-Escudero v. Tice-Menley, 58 F.3d 374, 377 (8th Cir.

1995)).        And with narrow exceptions, the court must return the

child to her country of habitual residence so that the courts of


        1
      "The Convention," however, "cease[s] to apply when the child
attains the age of 16 years." Convention, art. 4.
        2   "Preponderance of the evidence" means "more likely true than
not."       See United States v. Marino, 833 F.3d 1, 8 (1st Cir. 2016).
                                        - 3 -
that country can decide.         See Darín, 746 F.3d at 8 (recognizing

that "the Convention establishes a strong presumption in favor of

returning a wrongfully removed or retained child").

             As for the exceptions, we mention only two.             The first

is that a petition-receiving court need not order a return if

"there is a grave risk that . . . return would expose the child to

physical or psychological harm or otherwise place the child in an

intolerable situation," see Convention, art. 13(b)3 — and it's

important to keep in mind (for reasons that will become clear later

on) that when the alleged type of risk is "sexual abuse of a young

child,"    the   "policy   of   this    country    in   enforcing   the   .   . .

Convention . . . is to view sexual abuse as an intolerable

situation."      See Danaipour v. McLarey, 286 F.3d 1, 14-15 (1st Cir.

2002) (from now on, Danaipour I).4             The second is that a petition-

receiving court need not order a return if "the child objects to


     3 "'[G]rave' means a more than serious risk, but it need not
be an immediate risk."    Charalambous v. Charalambous, 627 F.3d
462, 467 (1st Cir. 2010).
     4   For anyone wondering:
     [T]he Convention assigns the task of making the "grave
     risk" determination to the court of the receiving
     country; here, this task includes the obligation to make
     any subsidiary factual findings needed to determine the
     nature and extent of any risk asserted as a defense to
     returning the child. The [Convention] does not give the
     courts of the country of habitual residence jurisdiction
     to answer the grave risk question.
Id. at 15.
                                       - 4 -
being returned and has attained an age and degree of maturity at

which it is appropriate to take account of [his or her] views."

See Convention, art. 13.

            So as not to diminish the Convention's policy against

unsavory     forum   shopping,    courts    construe   these    exceptions

narrowly, see Nicolson v. Pappalardo, 605 F.3d 100, 105 (1st Cir.

2010) — plus all facts supporting the grave-risk exception must be

proved     "by   clear   and   convincing   evidence,"5   and   all   facts

supporting the child-objection exception must be proved "by a

preponderance of the evidence."         See 22 U.S.C. § 9003(e)(2)(A),

(B).

                               The Abduction6

            Díaz-Alarcón and Flández-Marcel are Chilean nationals.

Flández-Marcel gave birth to their daughter, ADF, in 2008, in

Santiago, Chile.     Díaz-Alarcón and Flández-Marcel married in 2009,

separated in 2011, and divorced in 2014. They agreed that Flández-

Marcel would have patria potestad (meaning "parental power") over




       5
       "Clear and convincing evidence" means "highly probable,"
see Colorado v. New Mexico, 467 U.S. 310, 316 (1984), or
"reasonably certain," see Evidence:         Clear and Convincing
Evidence, Black's Law Dictionary 674 (10th ed. 2014). It falls
between preponderance of the evidence and proof beyond a reasonable
doubt. See Addington v. Texas, 441 U.S. 418, 425 (1979).
       6
       The relevant facts are not terribly complicated and are in
part stipulated.
                                   - 5 -
ADF, but that    Díaz-Alarcón would have a "direct and regular

relationship" with ADF through scheduled visits.

          Rewind to 2011, after Díaz-Alarcón and Flández-Marcel

had separated.   Flández-Marcel met and began dating Héctor Pérez-

Babilonia, a Puerto Rico resident. ADF eventually started spending

time with Pérez-Babilonia.    And in 2013 Díaz-Alarcón overheard ADF

call Pérez-Babilonia "dad."    Díaz-Alarcón, in his own words, "told

[ADF] off," explaining that Pérez-Babilonia "wasn't her dad."

          A few months later, Flández-Marcel had ADF evaluated by

a child psychologist.     And ADF got diagnosed with a possible

"[a]djustment [d]isorder."    The staff there also interviewed Díaz-

Alarcón, Flández-Marcel, and Pérez-Babilonia.     Díaz-Alarcón said

that both he and Flández-Marcel had verbally and psychologically

abused each other.   Flández-Marcel, for her part, accused Díaz-

Alarcón of psychologically abusing her.     After the interviews, a

social worker concluded that ADF had

     [a]lienation [s]yndrome, which describes the change that
     occurs when there are conflictive marital break ups, in
     which the children censure, criticize or reject one of
     their parents in an unjustified and/or exaggerated
     manner. This implies that one parent systematically and
     consciously programmes the children to denigrate the
     other.

Another social worker said that "it was demonstrated" that Díaz-

Alarcón had not "mistreat[ed]" ADF, though adding that "it was

demonstrated that the parents handled the family dynamic badly,

                                - 6 -
often being prone to including the girl in conflicts between

[them]."

            Fast forward to 2014, a couple of weeks after Díaz-

Alarcón and Flández-Marcel got divorced.    Flández-Marcel asked the

authorities in Santiago to issue a protective order for ADF and

her against Díaz-Alarcón, accusing him of having committed the

crime of "threatening with no aggravating circumstances against

persons" (excess capitalization omitted).    The authorities issued

the protective order, telling the police to give "priority status"

to calls from Flández-Marcel and to "periodic[ally] patrol[]" her

neighborhood.    But they eventually closed the matter after the

investigation unearthed no "information required to continue the

case."

            A few months later, in 2015, just before she married

Pérez-Babilonia, Flández-Marcel asked a Chilean family court for

permission to move to Puerto Rico for one year with ADF.     In her

petition, Flández-Marcel claimed that Díaz-Alarcón could not "be

located."   After somehow learning about the petition, Díaz-Alarcón

formally opposed Flández-Marcel's request in papers filed with the

court, saying she knew where he was and accusing her of being an

unfit mother.    The Chilean court then ordered Flández-Marcel to

undergo a psycho-social evaluation, focusing on her parenting



                               - 7 -
skills.     A social worker interviewed ADF as part of the process.

And ADF told her that Díaz-Alarcón

     is a fighter[;] he always hits with a closed fist. I've
     seen it. If I say something to him, he hits me. If I
     ask him a question, he hits me. If I ask him if we can
     go to the park, he hits me. That's how he was taught;
     violently. His mum and dad told me. Some other days he
     does not hit.

Asked by the social worker "to think of some positive aspects of

her dad," ADF said that Díaz-Alarcón is "a happy and loving person"

who "gives kisses" and "affection." But she added that he "doesn't

listen" when she tells him "he shouldn't hit [her] anymore."

            After reviewing the evaluation, the Chilean court pushed

Díaz-Alarcón and Flández-Marcel to reach an agreement.     And they

eventually did, agreeing, for example, that Flández-Marcel could

take ADF to Puerto Rico from December 26, 2015 to March 26, 2016

and that Díaz-Alarcón would have "constant communication" with ADF

as well as "additional days of visits" when she returned to Chile.

The Chilean court entered the agreement as a final and enforceable

judgment.

            According to Díaz-Alarcón, Flández-Marcel and ADF were

supposed to fly to Puerto Rico on December 26.      But because the

two did not have return tickets, they could not board the plane.

So they flew out on December 27 instead.

            Once there, Flández-Marcel enrolled ADF in school for

the semester starting in January 2016.    Early in January, ADF had
                                - 8 -
a Skype call with Díaz-Alarcón.      Flández-Marcel was present too.

ADF told Díaz-Alarcón that she never wanted to speak with him

again.   He asked her why.   And she, according to Flández-Marcel,

just screamed, "Cut, cut, cut."      So Flández-Marcel cut the call

short.

           Flández-Marcel repeatedly asked ADF what was going on.

According to Flández-Marcel, at first ADF would not say.     But one

day — after learning that Flández-Marcel was pregnant — ADF started

hitting her and then screamed, "Don't bathe me, don't bathe me,

don't bathe me."    "Who is going to bathe you?" Pérez-Babilonia

asked.   "Don't ask me," ADF said.

           At some point (apparently in January or February 2016),

ADF told Flández-Marcel and Pérez-Babilonia the following — at

least according to Flández-Marcel's expert witness, Dr. Carol

Romey:   During a visit to his home when she was 5, Díaz-Alarcón

had her take off her clothes to take a bath.        He took off his

clothes too, got into the tub, touched her "private parts," and

(per Pérez-Babilonia) had her touch his.     She then saw a "white-

yellow liquid come out of his penis."     After, he beat her "with a

slipper[] many times all over," walked "to the kitchen," and made

her "something to eat."7



     7 We will have more to say about this incident — on which so
much depends — later in this opinion.
                               - 9 -
            According to Díaz-Alarcón's expert witness, Dr. Judith

Mercado-Colón, a social worker at ADF's school recommended that

ADF undergo a psychological evaluation "because of emotional abuse

by her father."    The evaluation happened.      But if an evaluation

report exists, no one has told us where in the record we might

find it.8

            The deadline for ADF's return to Chile — March 26, 2016

— came and went without her showing up.   And she remains in Puerto

Rico to this very day.

                       Díaz-Alarcón's Petition

            Convinced that Flández-Marcel had wrongfully retained

ADF in violation of his custody rights, Díaz-Alarcón petitioned

Puerto Rico's federal district court under the Convention and

ICARA, seeking ADF's return.      Hoping to defeat Díaz-Alarcón's

petition, Flández-Marcel raised the grave-risk and child-objection

defenses.   The district judge referred the matter to a magistrate




     8 And because "[j]udges are not like pigs, hunting for
truffles" hidden in the record, we have no have no obligation to
look for it. See Rodríguez-Machado v. Shinseki, 700 F.3d 48, 50
(1st Cir. 2012) (per curiam) (alteration in original) (citation
and quotation marks omitted).
                               - 10 -
judge for an evidentiary hearing and a recommendation.              See 28

U.S.C. § 636(b)(1)(B).

                   The Magistrate Judge's Recommendation

               At the hearing, the magistrate judge heard testimony

from       Flández-Marcel,   Dr.   Romey   (Flández-Marcel's   expert,   who

submitted a report), Díaz-Alarcón, and Dr. Mercado-Colón (Díaz-

Alarcón's expert, who submitted a report as well).         The magistrate

judge also interviewed ADF (now aged ten) in chambers.9          Following

the close of evidence and the filing of post-hearing memos, the

magistrate judge issued a report and recommendation that reasoned

this way.

               On the grave-risk issue, the "critical question" being

whether Díaz-Alarcón "sexually abused" ADF, the magistrate judge

said        that   Dr.   Romey     (Flández-Marcel's   expert)   testified

"convincingly . . . that [ADF] had suffered serious trauma and now

suffers PTSD and anxiety."10 Dr. Romey, the magistrate judge added,



       9    Helpfully and commendably, the parties stipulated that
       Chile was [ADF's] country of habitual residence before
       [Flández-Marcel] removed her to Puerto Rico; the removal
       breached [Díaz-Alarcón's] custody rights under Chilean
       law; [Díaz-Alarcón] was exercising his custody rights
       when [Flández-Marcel] removed [ADF] to Puerto Rico;
       [ADF] was not sixteen years old; and Chile and the United
       States are both contracting states to the . . .
       Convention.
       10
        PTSD is short for post-traumatic stress disorder.                See
Danaipour I, 286 F.3d at 10.
                                     - 11 -
also found that ADF's relationship with Díaz-Alarcón is the only

"trigger" for her "PTSD and anxiety" and that "she would be at

grave risk of a psychotic break if she were to be placed under

[his] care . . . until she can process her experiences."    But in

the magistrate judge's telling, Dr. Romey's "purpose . . . was to

. . . assess[] . . . [ADF's] maturity" and current "psychological

state," and so did "not speak directly to whether [Díaz-Alarcón]

sexually abused [ADF]."   Dr. Mercado-Colón (Díaz-Alarcón's expert)

did "speak directly to that issue," the magistrate judge wrote.

And having assessed ADF, Dr. Mercado-Colón "concluded that there

was a suspicion of sexual abuse, just not by [Díaz-Alarcón]," given

some "incongruences" in ADF's statements about the incident.11

Ultimately, the magistrate judge said that while ADF "may be a

victim of sexual abuse, a preponderance of the evidence does not

show that [Díaz-Alarcón] abused her."

          On the child-objection issue, the magistrate judge said

that ADF "clearly objected to returning to Chile."     Summarizing

his in-chambers interview with ADF, the magistrate judge said that

she knows the difference between telling the truth and telling a

lie; is "intelligent and mature," having "a good understanding of

the decision facing her and specific reasons for her . . .



     11We will touch on the "incongruences" stuff in next part of
this opinion (discussing the district judge's decision).
                               - 12 -
opinion";12 and had not been "coached when she conveyed that she

wanted to stay in Puerto Rico" — "she did not appear to be unduly

influenced by the wishes of others such that her answers did not

change even after [the magistrate judge] impressed upon her the

importance of telling the truth." And, the magistrate judge found,

Dr. Romey's report and testimony — e.g., that she has a "level of

maturity clinically sufficient to be able to express her concerns

and wishes in a reasoned and coherent manner" — supported these

conclusions.

          Based on his findings, the magistrate judge recommended

that the district judge deny Díaz-Alarcón's petition because (in

his opinion), while Flández-Marcel cannot show "by clear and

convincing evidence that [ADF] would be at grave risk if returned

to Chile," she can show "by a preponderance of the evidence that

[ADF] is sufficiently mature to object to returning to Chile" and

that she did so object.




     12Staying with that topic, we think that another quote from
the magistrate judge deserves repeating here:
      Importantly, [ADF] had positive and negative things to
      say about her life both in Chile and Puerto Rico, which
      showed that it was not a black-and-white decision but
      rather one that she had weighed and considered. Her
      [mentioning] positive memories of Chile, including her
      favorite teacher and the beaches, shows a maturity in
      thought as she decided that those positive memories
      were outweighed by the negative.
                             - 13 -
                    The District Judge's Decision

          Both sides objected to the magistrate judge's report and

recommendation.     See 28 U.S.C. § 636(b)(1)(C); Fed. R. Civ. P.

72(b)(2). Giving the issues fresh-eyed "de novo review," see Mercy

Hosp., Inc. v. Mass. Nurses Ass'n, 429 F.3d 338, 343 (1st Cir.

2005), the district judge studied the materials and conducted her

own in-chambers interview of ADF. And the judge made the following

findings and rulings (the district judge addressed the issues in

an order different from the magistrate judge).

          On the child-objection issue, the district judge adopted

the magistrate judge's recommendation that Flández-Marcel proved

by a preponderance of the evidence that ADF "is sufficiently mature

to object to returning to Chile and that [she] does object to

returning." Still, the district judge noted that the fate of Díaz-

Alarcón's petition pivoted "primarily" on Flández-Marcel's defense

that ADF's "return to Chile would expose her to physical or

psychological harm or would otherwise place her in an intolerable

situation."

          On the grave-risk issue, the district judge highlighted

how the magistrate judge never asked ADF to go into the details of

the sexual abuse.    Quoting the magistrate judge's interview with

ADF, the district judge noted that after the magistrate judge asked

her to explain what she thought about whether she wanted "to go

                               - 14 -
back to Chile" or "stay in Puerto Rico," she replied, "[if] I go

to Chile he, if he [Díaz-Alarcón] finds out that I returned . . . ,

maybe he will come get me and he is going to do the same things he

did   before."     The   district   judge    then   pointed   out   that   the

magistrate judge later told her that "I know what you are talking

about.      So I am not going to make you tell me the whole story

again."      When ADF "referred to 'the same things he (the father)

did before,'" the district judge concluded, "she was clearly

referring to sexual abuse."13

             The district judge also disagreed with the magistrate

judge's suggestion that Dr. Romey did not speak to the sexual-

abuse allegation against Díaz-Alarcón. Dr. Romey, the judge wrote,

testified that Díaz-Alarcón's "presence" "would place [ADF] at

great risk of a psychotic break."            And, the district judge then

wrote, "when asked about which experiences caused this extreme

anxiety and stress to [ADF], Dr. Romey described in detail the

event narrated by [her] when her father went naked into the

bathtub, touched her private parts, masturbated and ejaculated."

             The district judge also noted that Dr. Romey saw "no

clinical indicators of exaggeration or unreliable reporting on

[ADF's] part." And the district judge indicated that ADF's "verbal




      13   The district judge added the "(the father)" parenthetical.
                                    - 15 -
statements" to Drs. Romey and Mercado-Colón and to the judge

herself were more notable for their commonalities than their

differences — the "common elements" being her saying that when she

was five or six, Díaz-Alarcón "told her she had to take a bath";

he took "his clothes off and go[t] into the bathtub with her"; he

"touched her private parts while both were in the bathtub"; and

"[s]he saw a yellow/white, thick liquid coming out of his penis."

            Dr. Mercado-Colón, the district judge noted, saw some

"inconsistencies" in the parties' accounts.           One example:      Dr.

Mercado-Colón testified that "it . . . appears from the statements

of   the   interviews"   that   ADF   told   Flández-Marcel    and   Pérez-

Babilonia that Díaz-Alarcón "bathe[d] her and forced her to bathe"

— but, according to Dr. Mercado-Colón, ADF told her (Dr. Mercado-

Colón) that Flández-Marcel and Díaz-Alarcón "did not bathe her

ever since she was a little girl."      Another example:      Dr. Mercado-

Colón testified that Pérez-Babilonia reported that ADF disclosed

that Díaz-Alarcón "touch[ed] [her] all [over] her body" — but, per

Dr. Mercado-Colón, ADF "only mentioned the genital area" to her

(Dr. Mercado-Colón).     Last example:       Dr. Mercado-Colón testified

that Pérez-Babilonia said that ADF stated that Díaz-Alarcón "asked

her [ADF] to touch him [Díaz-Alarcón]" — but, again according to

Dr. Mercado-Colón, ADF's "statements" do not indicate that Díaz-

Alarcón "asked her [ADF] to touch his [Díaz-Alarcón's] penis."

                                  - 16 -
          Yet the district judge found that every time Dr. Mercado-

Colón "revisited the subject of the sexual abuse, [ADF] would

provide the same details" — including "that her father touched her

private parts, that she was in the bathtub, and he went into the

bathtub naked, that a liquid came out of his penis that was yellow

and sticky."   And the district judge emphasized that "[t]hroughout

the several interview sessions and the repeated questioning by Dr.

Mercado[-Colón],   [ADF]   remained   steadfast   that   it   was   [Díaz-

Alarcón] who sexually abused her at his home."

          Noting how "vivid[]" her memory of her interview with

ADF was, the district judge later expressly found that ADF "had no

doubt of who was her wrongdoer."      "The who, what, when, and where

of this event [were] reported by [ADF] in the same manner to Dr.

Romey and [me]," the judge wrote.     And having canvassed the record

and considered the parties' arguments, the judge "conclud[ed],

without hesitation after assessing [ADF's] demeanor during the

entire interview in chambers, that her statement of sexual abuse

by [Díaz-Alarcón] is credible."       To quote again from the judge's

rescript, "[w]hat [ADF] described in the language of a child were

the acts of masturbation and ejaculation by her father after

touching her vagina" — a description that was "credible, honest

and heartfelt." So, the judge ruled, clear and convincing evidence



                                - 17 -
established that ADF faces a grave risk of harm if sent back to

Chile.

            And   with    that,   the   district    judge   dismissed   Díaz-

Alarcón's petition, precipitating this appeal.14

                            Standard of Review

     In deciding cases like this, we "must" remember to

     let district courts do what district courts do best —
     make factual findings — and steel ourselves to respect
     what they find.    While we review transcripts for a
     living, they listen to witnesses for a living. While we
     largely read briefs for a living, they assess the
     credibility of parties and witnesses for a living.

Taglieri v. Monasky, 907 F.3d 404, 408 (6th Cir. 2018); see also

Cumpiano v. Banco Santander P.R., 902 F.2d 148, 152 (1st Cir.

1990).      And   given   "the    unchallenged     superiority   of   [their]

factfinding ability," see Salve Regina College v. Russell, 499

U.S. 225, 233 (1991), we review their factfinding only for "clear

error," see Darín, 746 F.3d at 8.

            But showing clear error — which Díaz-Alarcón must do to

prevail — is no easy task.        See, e.g., United States v. Cates, 897

F.3d 349, 352 (1st Cir. 2018) (calling clear error's "heights . . .

difficult to scale").       It is not enough that a finding strikes us

as possibly or even probably wrong.          See Toye v. O'Donnell (In re

O'Donnell), 728 F.3d 41, 45 (1st Cir. 2013).                Rather, to quote



     14   We will note additional details as needed.
                                    - 18 -
ourselves quoting the Seventh Circuit, the finding must be "wrong

with the force of a 5 week old, unrefrigerated, dead fish."    See

id. at 46 (emphasis added) (quoting S Indus., Inc. v. Centra 2000,

Inc., 249 F.3d 625, 627 (7th Cir. 2001)).   Or, to quote ourselves

quoting the Supreme Court, we must be left "with the definite and

firm conviction" that the finding is "a mistake."       See United

States v. Nygren, 933 F.3d 76, 82 (1st Cir. 2019) (emphasis added)

(quoting United States v. U.S. Gypsum Co., 333 U.S. 364, 395

(1948)).

           So the judge's choice between competing, but rational,

views cannot be clearly erroneous.   See, e.g., Anderson v. City of

Bessemer City, 470 U.S. 564, 573-74 (1985). And plausible findings

based on witness credibility "can virtually never be clear error."

Id. at 575.    All of which means that we cannot stamp findings

clearly erroneous just because we might have decided the matter

differently.   See, e.g., Reich v. Newspapers of New Eng., Inc., 44

F.3d 1060, 1080 (1st Cir. 1995) (relying on Anderson, 470 U.S. at

574).

           To complete the picture, while we review the judge's

factual findings for clear error, we determine de novo whether she

interpreted and applied the Convention correctly.       See, e.g.,

Neergaard-Colón v. Neergaard, 752 F.3d 526, 530 (1st Cir. 2014).



                              - 19 -
                       Arguments and Analysis

            Díaz-Alarcón challenges the district judge's grave-risk

and child-objection conclusions.     We can begin —    and end — with

his grave-risk contentions, aware (to echo a point voiced by

Danaipour I) that

     [t]he policy under the Convention of . . . the United
     States government . . . is weighted towards protection
     of the child when there is credible evidence of sexual
     abuse, particularly when the child is so young and when
     the allegations involve abuse by a parent. This policy
     informs the grave risk analysis.

286 F.3d at 16.

            Díaz-Alarcón's first set of arguments is directed at the

district     judge's   handling    of   the      magistrate   judge's

recommendations — to no avail, Flández-Marcel argues; and we agree

with her.

            For example, Díaz-Alarcón essentially claims that the

district judge erred by not seconding the magistrate judge's

recommendation to accept Dr. Mercado-Colón 's no-sexual-abuse-by-

Díaz-Alarcón conclusion.      Insisting that "Dr. Mercado[-Colón]

testified that [ADF] would not be in grave risk to suffer harm if

return[ed]," he also implies that the district judge had no choice

but to find as the magistrate judge did.        But as Flández-Marcel

points out, the problem for Díaz-Alarcón is that the district judge

was legally empowered to "accept, reject, or modify, in whole or

in part, the [magistrate judge's] findings or recommendations,"
                               - 20 -
see 28 U.S.C. § 636(b)(1); and she was legally required to "make

a de novo determination of those portions of the [magistrate

judge's] report or specified proposed findings or recommendations

to which objection is made," see id.     To be fair, the evidence

certainly points in conflicting directions in spots.     Yet Díaz-

Alarcón cannot meet his burden of showing clear error merely by

pointing to competing testimony.    See Anderson, 470 U.S. at 573-

74; see also United States v. Flete-Garcia, 925 F.3d 17, 26 (1st

Cir. 2019) (explaining that if there are two permissible views of

the evidence, "a [district] court's choice between those two

competing [views] cannot be clearly erroneous").    And ultimately,

the evidence that the district judge highlighted — which included

statements by ADF that she found "credible, honest and heartfelt"

— lend the kind of strength necessary for her grave-risk findings

to pass clear-error inspection.    See Anderson, 470 U.S. at 575.

          Trying to undercut the plausibility of ADF's interview

statements, Díaz-Alarcón says in the grave-risk section of his

brief that Flández-Marcel "employ[ed] undue influence."     But he

does not seriously develop his single-sentence suggestion — for

instance, he does not adequately explain why the district judge

clearly erred in finding (based on her personal observation of

ADF) that ADF's statements were "honest and heartfelt," a finding

that runs counter to his undue-influence intimation.         So we

                             - 21 -
consider the suggestion waived.        See, e.g., United States v.

Zannino, 895 F.2d 1, 17 (1st Cir. 1990) (admonishing that "issues

adverted to in a perfunctory manner, unaccompanied by some effort

at developed argumentation, are deemed waived").

          Wait a minute, says Díaz-Alarcón.     Caselaw holds that

"absent special circumstances, a district judge may not reject the

credibility determination of a magistrate judge without first

hearing the testimony" herself.   See United States v. Hernández-

Rodríguez, 443 F.3d 138, 148 (1st Cir. 2006).     And, his argument

continues, the district judge here flouted this rule by rejecting

the magistrate judge's "credibility determination" of Dr. Mercado-

Colón "without hearing [her] live testimony."     But we agree with

Flández-Marcel that the district judge committed no such error.

And that is because — in responding to Díaz-Alarcón's motion for

a free transcript — the district judge stated in no uncertain terms

that she "did not reject any credibility determination(s) made by

the Magistrate-Judge concerning [Dr. Mercado-Colón's] findings."15



     15 28 U.S.C. § 753(f) pertinently provides that a party
requesting a free transcript must show "that the appeal is not
frivolous (but presents a substantial question)." In his motion,
Díaz-Alarcón argued (among other things) that his credibility-
rejection argument was nonfrivolous. Because he "imputed, without
basis, that the [district judge] rejected determinations of
credibility by the Magistrate-Judge regarding testimony that was
dispositive of the grave risk of harm defense," and because no
other "substantial questions are presented on appeal," the judge
denied his motion.
                              - 22 -
Instead, she simply considered Dr. Mercado-Colón's findings in the

context of all the evidence — i.e., she kicked around each bit of

"'evidence submitted to the Magistrate-Judge,'" including "the

personal interview of the minor in chambers and the testimonies of

the parents" — in ruling that Flández-Marcel had established the

grave-risk defense.

          Díaz-Alarcón also implies that the district judge had to

follow the magistrate judge's lead and side with Dr. Mercado-Colón

over Dr. Romey, because Dr. Romey relied on "a narration of events

made . . . to be used in this judicial proceeding."        But he

provides no on-point authority for why that matters. See generally

Town of Norwood v. FERC, 202 F.3d 392, 405 (1st Cir. 2000)

(emphasizing that "developing a sustained argument out of . . .

legal precedents" is a litigant's job, not ours). Anyway, it seems

clear to us that Dr. Mercado-Colón did the same thing.     And so

either way, this aspect of    Díaz-Alarcón's argument is not a

difference-maker.

          Nor is Díaz-Alarcón's assertion that the district judge

had to accept the magistrate judge's recommendation because "Dr.

Mercado[-Colón] was the only expert in forensic sexual abuse

evaluation."   After all, Danaipour I makes clear that sometimes

trial judges can "find that sexual abuse did or did not occur

without the benefit of a full forensic evaluation."   See 286 F.3d

                             - 23 -
at 19 n.14.     And Díaz-Alarcón has not persuasively explained why

this is not one of those times.

             Díaz-Alarcón's next set of arguments takes aim at the

district judge's interview of ADF — again to no avail, Flández-

Marcel says; and again we agree with her.

             For starters, Díaz-Alarcón complains that the district

judge "call[ed] [ADF] for an interview in private . . . on the

sexual abuse allegation" — an interview that he says lacked

"guarantees of trustworthiness."             But he gives us no indication

that   he    objected    to   the   chambers-interview     procedure.        See

generally Reyes-García v. Rodríguez & Del Valle, Inc., 82 F.3d 11,

14 (1st Cir. 1996) (noting that an appellant pushing an argument

on appeal must show us that he "seasonably advanced and properly

preserved [it] in the lower court").           Nor does he develop here any

critique of that procedure beyond arguing that the sex-abuse

questioning was unrelated to the ADF's objection to returning to

Chile — an argument that falls on its own weight.             So we deem any

challenge on this score waived, see Zannino, 895 F.2d at 17,

without     offering    any   opinion   on    the   procedure's   adequacy   or

fairness.

             Repeating his just-rejected argument (that the district

judge had to accept the magistrate judge's view of the record),

Díaz-Alarcón contends that the district judge's "consideration of

                                     - 24 -
new evidence" — i.e., the district judge's interview of ADF —

amounts    to   "an   abuse   of   discretion"    in   "this   case."     This

contention does not move the needle, however, because the law

allowed her to "receive further evidence" as she decided de novo

whether to "accept, reject, or modify" the magistrate judge's

proposed findings or legal conclusions. See 28 U.S.C. § 636(b)(1);

see also Fed. R. Civ. P. 72(b)(3).

            Moving on, Díaz-Alarcón writes that the district judge

could have ordered ADF back to Chile without putting her in harm's

way by imposing "undertakings" — i.e., enforceable conditions on

her return designed to keep her safe.            See Danaipour I, 286 F.3d

at 21-23; see also Danaipour v. McLarey, 386 F.3d 289, 302-03 (1st

Cir. 2004) (hereinafter, Danaipour II).             Separating permissible

undertakings     from   impermissible     ones    is    complicated     stuff,

however.    See Danaipour I, 286 F.3d at 21-23.          There are concerns

for "international comity" — an American court, for example, should

do nothing that "would smack of coercion of the foreign court."

Id. at 23-24; see also id. at 22 (discussing the need to "avoid

the unseemliness of a U.S. court issuing orders for a foreign court

to enforce, and the foreign court's possible noncompliance").             And

there are concerns about "the appropriateness of undertakings when

the abducting parent claims to be protecting the child from abuse,"

id. at 22 — some "authority," for instance, "indicat[es] that

                                    - 25 -
undertakings should be used more sparingly when there is evidence

that the abducting parent is attempting to protect the child from

abuse," id. at 25; see also Danaipour II, 386 F.3d at 293 (holding

that a district court's supportable finding that a child's return

"would cause grave harm" makes "immaterial" petitioner's claim

that the courts in the child's country of habitual residence "could

take ameliorative actions to prevent further harm," adding that

"[i]n    such    circumstances,         [the    Convention]     does    not    require

separate consideration either of undertakings or of steps which

might    be     taken    by    the     courts   of    the   country     of    habitual

residence").         Díaz-Alarcón        has    the   burden    of    proof    on   the

undertakings issue.           See Danaipour I, 286 F.3d at 21, 26.             But he

deals with none of these complexities.                  Which is not the way to

turn    the   tide      in   his    favor,   since    failing   to     give   "serious

treatment [to] a complex issue . . . is not adequate to preserve

the claim on appeal."              See Tayag v. Lahey Clinic Hosp., Inc., 632

F.3d 788, 792 (1st Cir. 2011).

              Díaz-Alarcón hinges his last set of arguments on caselaw

indicating that a district judge "has discretion to order return

even where such return poses a grave risk of harm or threatens to

place the child in an intolerable situation."                        See Lozano v.

Montoya Alvarez, 572 U.S. 1, 21 (2014) (Alito, J., concurring)

(quotation marks omitted); see also Mauvais v. Herisse, 772 F.3d

                                         - 26 -
6, 11 (1st Cir. 2014).    As he sees it, the district judge "abused

[her] discretion by not giving sufficient weight[,] if any," to

Flández-Marcel's "inequitable conduct" (e.g., "conceal[ing]" ADF

from him and "undu[ly] influenc[ing]" her), to ADF's "interests"

(e.g.,   Flández-Marcel    "disrupt[ed]     the    strong   and   stable

relationships [ADF] had in Chile"), and to the Convention's "aims

and objectives." Like Flández-Marcel, we see no reason to reverse.

          Consider Díaz-Alarcón's contention that the district

judge had no "awareness of [her] responsibility to weigh[] the

relevant factors."     He played up these factors below, however.

And the district judge said that she considered the "evidence

presented."    "While a fuller explanation might have been helpful,"

we know "that the absence of a more detailed explanation does not

amount to an abuse of discretion."      See Yaman v. Yaman, 730 F.3d

1, 22 (1st Cir. 2013).    As for the rest of his argument, his real

complaint is essentially that the district judge should have given

controlling weight to the interests that cut in favor of return.

But "[s]uch relative weighting of interests by the district court

. . . is not for [us] to second-guess, and especially not on an

abuse of discretion analysis."    See id.

          Time for a summary.     An appellant's odds of winning a

clear-error challenge are not very good.          See, e.g., Cates, 897

F.3d at 352.    This is especially so here, given how the district

                               - 27 -
judge was uniquely situated to gauge ADF's credibility. See, e.g.,

United States v. McGregor, 650 F.3d 813, 820 (1st Cir. 2011).

Sure,    maybe     the   district    judge    could   have   made    different

credibility findings or weighed the evidence differently.                 But

that    does    not   make   her   at-issue   findings   clearly    erroneous.

Ultimately, because none of Díaz-Alarcón's arguments leaves us

with a "definite or firm conviction" that the district judge made

"a mistake" or, more odoriferously, convinces us that she was

"wrong with the force of a 5 week old, unrefrigerated, dead fish,"

see Toye, 728 F.3d at 46, we cannot reverse her on the grave-risk

issue — even if we would have reached a different a conclusion,

see Anderson, 470 U.S. at 573.          And given this ruling, we have no

need to decide the child-objection issue.

                                   Final Words

               For the reasons recorded above, we affirm the judgment

entered below.        No costs to either party.




                                     - 28 -
