                               In the

    United States Court of Appeals
                 For the Seventh Circuit
                     ____________________
No. 15-2983
RAUL SALAZAR GARCIA,
                                                 Petitioner-Appellee,

                                 v.

EMELY GALVAN PINELO,
                                              Respondent-Appellant.
                     ____________________

         Appeal from the United States District Court for the
           Northern District of Illinois, Eastern Division.
            No. 14 C 09644 — Edmund E. Chang, Judge.
                     ____________________

  ARGUED DECEMBER 3, 2015 — DECIDED DECEMBER 22, 2015
                     ____________________

   Before WOOD, Chief Judge, and MANION and HAMILTON,
Circuit Judges.
    WOOD, Chief Judge. Raul Salazar Garcia and Emely Galvan
Pinelo, both Mexican citizens, dated only briefly in 2001 and
early 2002. But their relationship had one lasting conse-
quence: in October 2002, Galvan gave birth to a child, D.S., in
Monterrey, Nuevo León, Mexico. Although Galvan at all
times has had physical custody of D.S., Salazar played an ac-
tive part in the child’s life. In 2013, Galvan and D.S. moved to
2                                                   No. 15-2983

Chicago. Salazar now seeks D.S.’s return to Mexico under the
Hague Convention on Civil Aspects of International Child
Abduction, T.I.A.S. No. 11670, 1343 U.N.T.S. 89 (Oct. 25,
1980), to which both Mexico and the United States are parties.
In the United States, it has been implemented through the In-
ternational Child Abduction Remedies Act (ICARA), 22
U.S.C. § 9001 et seq. The Convention “entitles a person whose
child has wrongfully been removed to the United States in vi-
olation of the Convention to petition for return of the child to
the child’s country of ‘habitual residence,’ unless certain ex-
ceptions apply.” Norinder v. Fuentes, 657 F.3d 526, 529 (7th Cir.
2011). Once the child is in that country, the local courts are
empowered to resolve any questions about custody, support,
or other family law matters.
    This case presents us with three questions. First, we must
determine whether, for the purpose of determining “rights of
custody” under the Convention, a petitioner’s proof of for-
eign law should be treated as a question of law or a question
of fact. Second, we must decide whether Salazar has shown
that he had sufficient rights over D.S. at the time of the reten-
tion to trigger the Convention’s protections. Finally, we must
evaluate whether the district court went beyond the bounds
of its discretion when it declined to allow D.S. to stay in the
United States pursuant to the Convention’s mature-child ex-
ception.
    We conclude that the Hague Convention is no exception
to the general rule, reflected in Federal Rule of Civil Proce-
dure 44.1, that an issue about foreign law is a question of law,
not fact, for purposes of litigation in federal court. We agree
with the district court that Salazar had the necessary custodial
right (referred to in Mexico either by its Latin name, patria
No. 15-2983                                                   3

potestas, or occasionally by its Spanish name, patria potestad)
over D.S. at the time when Galvan refused to permit his return
to Mexico. Because D.S.’s habitual residence is Mexico (a
point that is now uncontested), Galvan’s retention of D.S. is
wrongful under the Convention. Finally, although we con-
sider it a close question, we conclude that the district court
had adequate reason to refuse to defer to D.S.’s indications
that he prefers to stay in the United States. We therefore af-
firm the district court’s judgment.
                               I
   As we noted, Salazar and Galvan’s brief relationship left
them with a son, D.S., who was born in October 2002. They
never married, and they never lived together. In 2006, a
Nuevo León court entered a custody order recognizing Gal-
van and Salazar as D.S.’s parents. The court awarded physical
custody of D.S. to Galvan and gave Salazar weekly visitation
rights. For the first ten years of his life, D.S. lived with his
mother in Monterrey, and Salazar visited regularly in accord-
ance with the custody agreement.
    In late 2012, Galvan requested Salazar’s assistance in ob-
taining a passport and visa for D.S. to visit the United States.
She intended to visit relatives in Texas and then to take D.S.
to either Disney World or Disneyland. Before that trip took
place, however, she became engaged to an American citizen
named Rogelio Hernandez, whom she married in July 2013.
Around this time, she decided that she wanted to move with
D.S. to the United States. While Galvan had told Salazar about
her initial plans to travel with D.S. to the United States as a
tourist, she did not advise him of her change in plans. Salazar
became suspicious, however, when he saw news of Galvan’s
4                                                  No. 15-2983

engagement on Facebook. That led to a meeting among Gal-
van, Salazar, and D.S. on July 30, 2013, at a Starbucks in Mon-
terrey. Galvan and Salazar agreed then that D.S. would move
to Chicago with his mother and stay there for one school year.
What was not clear was what was to happen at the end of that
year. Salazar recalls that the parties agreed that D.S.’s wishes
would be dispositive, and Galvan thought that the two par-
ents simply agreed to conduct further discussions.
    As planned, Galvan and D.S. moved to Chicago on August
15, 2013, and D.S. enrolled in school. Throughout the year,
D.S. and Salazar kept in touch through Skype and Facebook.
D.S. visited his father in Mexico for the Christmas holiday in
December 2013. In his conversations with Salazar, D.S. said
that he wanted to return to Mexico at the end of the school
year; at the same time, he was telling his mother that he
wanted to stay in Chicago.
    Believing that the parties had agreed that D.S.’s wishes
would govern his placement after the 2013-14 school year,
and further believing that D.S. wanted to return to Mexico,
Salazar showed up in Chicago in July 2014 with two return
tickets to Mexico, one for him and one for D.S. This time it
was Galvan who was taken by surprise: she believed that Sal-
azar was in Chicago only to visit. Salazar and D.S. spent sev-
eral days as tourists in Chicago. On July 21, 2014, in another
Starbucks, D.S. and Salazar announced to Galvan that D.S.
was moving back to Mexico with Salazar. Galvan did not be-
lieve that he wanted to return, nor did she think that she had
an obligation to defer to his wishes. Salazar left the Starbucks
with D.S., but the Chicago Police later contacted Salazar and
instructed him to return D.S. to Galvan. Salazar complied. He
returned alone to Monterrey, where he filed the petition that
No. 15-2983                                                     5

is now before us. The Mexican Central Authority transferred
the petition to the United States Department of State, which
filed it in the district court on December 2, 2014.
    The district court appointed a guardian ad litem for D.S. At
first, D.S. did not indicate a preference for either Mexico or
Chicago. Over time, however, his views evolved. In late April
2015, D.S. told his guardian that he wanted to stay in Chicago.
The district court conducted an in-camera hearing with D.S.—
by then 13 years old—to ascertain his views. D.S. told the
judge that he preferred to stay in Chicago because it had bet-
ter schools and opportunities, was safer, and he did not want
his mother to be forced to pay Salazar’s costs and fees. He in-
dicated that he wanted to finish eighth grade in Chicago, but
that if he were not admitted to a good high school after eighth
grade, he might return to Mexico. While he stated a prefer-
ence for remaining in Chicago, he did not object to returning
to Mexico.
    At some point while all this was happening, Galvan’s im-
migration status took a turn for the worse. We go into more
detail below, but for present purposes it is enough to say that
both she and D.S. had overstayed their tourist visas and had
no other basis for staying in the United States. This meant, her
immigration lawyer told her, that she probably could not
travel outside the United States, even to visit D.S. This news
prompted Galvan to request a second in-camera hearing be-
tween the judge and D.S. She believed her immigration diffi-
culties would change D.S.’s mind: since she would be unable
to visit him in Mexico, it would be very difficult for D.S. to see
his mother, possibly for a very long time. The district court
obliged. During the second hearing, D.S. more clearly ob-
jected to returning to Mexico. While he gave several reasons
6                                                 No. 15-2983

for doing so, he also indicated that he would not object to re-
turning if Galvan’s immigration situation were quickly re-
solved and she could travel freely between the United States
and Mexico.
    On August 21, 2015, the district court held an evidentiary
hearing at which it received testimony from Salazar, Galvan,
and Hernandez on the issues of the scope of Salazar and Gal-
van’s July 2013 agreement and whether the United States or
Mexico was D.S.’s country of habitual residence. In orders en-
tered on August 16 and August 28, 2015, the court granted
summary judgment for Salazar. It found as a matter of fact
that when Salazar and Galvan met in the Monterrey Starbucks
in July 2013, they agreed that it would be D.S.’s decision
whether to remain in Chicago after one school year had
passed. It also found that Mexico was D.S.’s country of habit-
ual residence. Applying the law of the Mexican state of Nuevo
León, the court found that Salazar had the right of patria
potestas over D.S., and that this qualifies as a “right of cus-
tody” for purposes of the Convention. (We refer occasionally
to “Mexican law” in this opinion; we intend that phrase to en-
compass both Mexican federal law, such as the Convention,
and the state law of Nuevo León.) This meant, the court held,
that as of the summer of 2014 D.S. was wrongfully retained.
That meant that he had to be returned to Mexico, unless the
mature-child exception recognized by the Convention was
met (i.e. D.S. was mature enough to make his own decision,
and his decision was to stay in the United States). The court
found that D.S. had eventually objected to returning to Mex-
ico, and that he was sufficiently mature. It nonetheless de-
clined to give effect to D.S.’s wishes, because it determined
that doing so would not serve the purposes of the Conven-
tion. It thus ordered D.S. to be returned to Mexico.
No. 15-2983                                                      7

    Galvan has appealed. She offers three reasons for rejecting
the district court’s decision. First, she argues that Salazar did
not prove his custody rights by a preponderance of the evi-
dence, and thus that there is no basis for finding that D.S. was
wrongfully retained. Second, she asserts that as a matter of
Mexican law, Salazar does not have the necessary custody
rights for Convention purposes. Finally, she argues that the
district court abused its discretion by declining to apply the
Convention’s mature-child exception. She does not contest
the district court’s findings with regard to D.S.’s country of
habitual residence or the scope of the July 2013 agreement.
                                II
    We review the district court’s findings of fact for clear er-
ror, and its conclusions of law—whether American, foreign,
or international—de novo. See Koch v. Koch, 450 F.3d 703, 710
(7th Cir. 2006) (collecting cases); Friedrich v. Friedrich, 78 F.3d
1060, 1064 (6th Cir. 1996) (citing Fed. R. Civ. P. 44.1 (“In deter-
mining foreign law … [t]he court’s determination must be
treated as a ruling on a question of law.”)).
    At bottom, the Hague Convention “is an anti-abduction
treaty.” Redmond v. Redmond, 724 F.3d 729, 739 (7th Cir. 2013).
It has two purposes: “to secure the prompt return of children
wrongfully removed to or retained in any Contracting State,”
and “to ensure that rights of custody and of access under the
law of one Contracting State are effectively respected in the
other Contracting States.” Hague Convention art. 1, T.I.A.S.
No. 11670. It is meant “to deter parents from absconding with
their children and crossing international borders in the hopes
of obtaining a favorable custody determination in a friendlier
jurisdiction.” Walker v. Walker, 701 F.3d 1110, 1116 (7th Cir.
2012).
8                                                   No. 15-2983

    In order to accomplish its objectives, the Convention “em-
ploys a ‘remedy of return.’” Ortiz v. Martinez, 789 F.3d 722,
728 (7th Cir. 2015) (quoting Kahn v. Fatima, 680 F.3d 781, 783
(7th Cir. 2011)). This remedy “entitles a person whose child
has wrongfully been [retained in] the United States in viola-
tion of the Convention to petition for return of the child to the
child's country of ‘habitual residence.’” Norinder, 657 F.3d at
529. A removal or retention is wrongful under the Convention
where “it is in breach of rights of custody attributed to a per-
son … under the law of the State in which the child was ha-
bitually resident immediately before the removal or reten-
tion,” and those rights were “actually exercised … or would
have been so exercised but for the removal or retention” at the
time of the removal or retention. Hague Convention art. 3,
T.I.A.S. No. 11670.
    Several principles of the Convention have a bearing on
this case. First, it is not our prerogative “to settle a custody
dispute.” Ortiz, 789 F.3d at 728; Hague Convention art. 19,
T.I.A.S. No. 11670 (“A decision under this Convention con-
cerning the return of the child shall not be taken to be a deter-
mination on the merits of any custody issue.”); 22 U.S.C.
§ 9001(b)(4). Rather, the Convention is designed to restore the
pre-removal status quo. See Ortiz, 789 F.3d at 728. More
broadly, it “seeks ... to prevent a later decision on the matter
[from] being influenced by a change of circumstances brought
about through unilateral action by one of the parties.” Elisa
Pérez–Vera, Explanatory Report: Hague Conference on Private In-
ternational Law ¶ 71, in 3 Acts and Documents of the Fourteenth
Session 426, 447–48 (1980). Finally, it is a “basic principle” of
the Convention “that a child’s country of habitual residence
No. 15-2983                                                      9

is ‘best placed to decide upon questions of custody and ac-
cess.’” Whallon v. Lynn, 230 F.3d 450, 456 (1st Cir. 2000) (quot-
ing Explanatory Report ¶ 34, at 434–35).
                                A
    We turn first to the question whether Salazar must
“prove” the content of the relevant Mexican law by a prepon-
derance of the evidence, as if it were a question of fact, or if
this is a straightforward question of law for the court. Galvan
takes the former position and asserts that Salazar failed to
prove that the rights he possesses under Mexican law qualify
for protection under the Convention. Thus, she concludes, the
district court should have dismissed his petition.
    Whatever one might think of Galvan’s position in the ab-
stract, it does not stand up to scrutiny under the governing
rules of procedure. Federal Rule of Civil Procedure 44.1 states
that “[i]n determining foreign law, the court may consider
any relevant material or source, including testimony, whether
or not submitted by a party or admissible under the Federal
Rules of Evidence.” It specifies that “[t]he court’s determina-
tion must be treated as a ruling on a question of law.” Id. And
this is not a rule exclusively for the district courts. To the con-
trary, “[i]n determining these questions of [foreign] law, both
trial and appellate courts are urged to research and analyze
foreign law independently.” Twohy v. First Nat’l Bank of Chi-
cago, 758 F.2d 1185, 1193 (7th Cir. 1985). This is because “one
of the policies inherent in Rule 44.1 is that whenever possible
issues of foreign law should be resolved on their merits and
on the basis of a full evaluation of the available materials.” Id.
(quoting 9 CHARLES ALAN WRIGHT & ARTHUR R. MILLER,
FEDERAL PRACTICE AND PROCEDURE § 2444 (1971)).
10                                                   No. 15-2983

    Galvan argues that two cases—In re Griffin Trading Co., 683
F.3d 819, 824 (7th Cir. 2012), and Banque Libanaise Pour Le Com-
merce v. Khreich, 915 F.2d 1000, 1006 (5th Cir. 1990)—support
her position, but they do not. Griffin and Khreich address the
distinct issue of choice of law, which is not contested in our
case. The parties can waive a choice-of-law argument, but the
court has an independent responsibility to ascertain the con-
tent of any given law. See Twohy, 758 F.2d at 1193; Curley v.
AMR Corp., 153 F.3d 5, 12 (2d Cir. 1998). Indeed, the court is
not limited to materials submitted by the parties when it un-
dertakes this job: it is free to conduct its own research.
    A central issue in the present case is whether Salazar had
sufficient custody rights over D.S. to be entitled to relief under
the Convention and ICARA. The answer depends on Mexican
law, and thus the inquiry lies comfortably within Rule 44.1’s
ambit. In this respect, the U.S. federal rules of procedure are
entirely consistent with the Convention, which is based on re-
spect for the law of the country of the child’s habitual resi-
dence. Whallon, 230 F.3d at 456, which in turn refers to Explan-
atory Report ¶ 34, at 434–35 (also noting at ¶ 67 that “the law
of the child’s habitual residence is invoked in the widest pos-
sible sense.”).
   Galvan attempts to avoid this logic by arguing that the
bundle of fact and law on which the district court made its
decision had to be treated as a question of fact. But she has no
quarrel with the facts that Salazar presented; instead, she says
that Salazar did not produce enough evidence of the law of
Nuevo León to permit the district court to resolve the issue.
The district court was not, however, limited to the evidence
Salazar presented (and for what it is worth, he did present
some). The district court was required to find that it was more
No. 15-2983                                                   11

likely than not, given its independent analysis of the relevant
Mexican law and its consideration of Salazar’s factual evi-
dence, that the rights Salazar possessed are protected by the
Convention. The important question, to which we now turn,
is whether the court came to the right conclusion.
                               B
    A removal or retention is wrongful if (1) “in breach of
rights of custody … under the law of the state in which the
child was habitually resident immediately before the removal
or retention”; and (2) “at the time of removal or retention
those rights were exercised … or would have been so exer-
cised but for the removal or retention.” Hague Convention
art. 3, T.I.A.S. No. 11670. Because D.S.’s habitual residence at
the time of the retention was the Mexican state of Nuevo
León, the governing law is that state’s Civil Code.
    Salazar relies on a doctrine known as patria potestas to sup-
port his claim. Patria potestas is a concept derived from the Ro-
man civil law tradition; literally, the Latin words mean “the
power of the father.” Historically, the power of the father over
his children was absolute, both in scope and to the exclusion
of others. Patricia Begné, Parental Authority and Child Custody
in Mexico, 39 Fam. L.Q. 527, 529 (2005). Under Roman and
German law, patria potestas permitted a father to discipline his
children in any way, up to and including by death; that power
endured throughout the father’s life. Id. Mexico’s codes of
1870 and 1884 conveyed patria potestas first to the father of a
child and only secondarily to the mother. Id. It was only in
1928 that the Civil Code began the process of eliminating its
gender bias. Id.
12                                                    No. 15-2983

    Today, patria potestas is based on the central values of “fair-
ness and reciprocity”; it is a gender-neutral legal regime that
regulates the relationship between parents (or parent-like fig-
ures) and their children. Id. at 530 (citing Código Civil para el
Distrito Federal art. 411); see also Civil Code for Nuevo León
(CCNL) art. 411 (“Respect and mutual consideration shall
govern the relationship between parents and children.”). This
court has recognized patria potestas as a “right[] of custody”
within the meaning of the Convention. See Altamiranda Vale v.
Avila, 538 F.3d 581, 587 (7th Cir. 2008) (“When the parent who
does not receive physical custody is given the rights and du-
ties of patria potestas, he has custody rights within the meaning
of the Hague Convention.”). While we interpreted Venezue-
lan law in Avila, the concept of patria potestas is substantially
the same under the law of Nuevo León.
    Galvan does not dispute that patria potestas constitutes a
“right of custody” under the Convention. Cf. Abbott v. Abbott,
560 U.S. 1 (2010) (noncustodial parent’s ne exeat right is a
“right of custody” for purposes of the Convention). Rather,
she denies that Salazar has such a right. She does so on two
bases: primarily, she asserts that he never possessed the patria
potestas right over D.S.; her back-up position is that any patria
potestas right he may have held was extinguished by the 2006
custody agreement.
                                1
    Galvan’s more ambitious argument—that Salazar never
possessed patria potestas over D.S.—was never squarely pre-
sented to the district court. In her reply brief, Galvan argues
that she nevertheless did not waive it because it was an essen-
tial part of her argument that “the parties’ rights were limited
to what was specified in the [2006] court order.” This assertion
No. 15-2983                                                     13

is not borne out by Galvan’s summary judgment submission,
which at no point asserts that Salazar lacked patria potestas be-
fore the custody agreement. This probably constitutes waiver
of the point. Even if it were merely forfeited, however, we
think that Salazar has the better of the argument.
   Galvan relies on article 416 of the Civil Code for Nuevo
León, because it is the only provision that expressly applies to
parents who never lived together. Article 416 states:
   When both parents have recognized a child born out of
   wedlock and they live together, they will jointly exert
   parental authority/responsibility (patria potestas). If
   they do not live together, what is established by articles
   380 and 381 will apply to grant custody of the child.
Articles 380 and 381 describe the procedures for establishing
custody depending on the timing of the parents’ recognition
of the child. Neither mentions patria potestas.
    Galvan argues that article 416’s mention of the patria
potestas right with regard to parents who live together—and
especially the article’s silence on this point with regard to par-
ents who do not—indicates that patria potestas does not attach
automatically when the parents never cohabitated. She finds
support for this position in article 417, which provides that
“[w]hen the parents of a child born out of wedlock that were
living together[] separate, both retain parental authority/re-
sponsibility (patria potestas).” This article, too, has nothing to
say about unmarried parents who never lived together.
   Salazar counters that patria potestas is a default doctrine
that attaches automatically to both birth parents upon their
acknowledgment of parentage. He provided the district court
with a certificate from the Mexican Central Authority stating
14                                                   No. 15-2983

that “[a]ccording to Mexican Law, individuals acquire paren-
tal rights (patria potestad) over a child since the moment of
birth, or registration before the civil registry as a result of an
acknowledgment of paternity.” Salazar also notes that article
414 states that “[p]arental authority/responsibility (patria
potestas) is exerted jointly by both parents.” Other authorities
support this view. The Begné article suggests that patria
potestas is “mandatory” and “not transferable.” Begné, Paren-
tal Authority, 39 Fam. L.Q. at 530 (“Parental authority has rel-
evant social significance, as it involves the fulfillment of the
most important responsibility that a person can assume … . It
is therefore considered by law to be mandatory.”). “Parents
exercising their authority ‘always keep … the right to shelter
their descendants.’” A.A.M. v. J.L.R.C., 840 F. Supp. 2d 624,
634–35 (E.D.N.Y. 2012) (quoting JOSÉ ANTONIO MÁRQUEZ
GONZÁLEZ, FAMILY LAW IN MEXICO 81 (2011)). “The [Mexican]
Supreme Court has ruled that … ‘patria potesta[d], as a general
rule, must be exercised by two parents jointly, and only as an
exception may it be exercised by one parent.’” Saldivar v.
Rodela, 879 F. Supp. 2d 610, 624 (W.D. Tex. 2012) (quoting
STEPHEN ZAMORA ET AL., MEXICAN LAW 459–60 (2004)). Sala-
zar argues that article 416’s second sentence is better read as
addressing the rules for physical custody in the case of un-
married, noncohabiting parents, not as a statement on
broader rights of parental authority. After all, if the parents
are cohabiting, it makes sense to assume that they will exer-
cise joint custody.
   Galvan’s textual argument depends entirely on the maxim
expressio unius est exclusio alterius (to include one thing is to
exclude another). But even assuming that this notion exists in
Mexican law and operates there just as it does in the United
No. 15-2983                                                    15

States, it is at best “an aid to determine the intent of the stat-
ute.” 82 C.J.S. Statutes § 424 (2015). Even if we set aside the
certificate from the Mexican Central Authority (and we see no
reason to do so), nothing justifies our applying the maxim
here. Patria potestas is central to Mexican family law. See
Lieberman v. Tabachnik, 625 F. Supp. 2d 1109, 1118 (D. Colo.
2008) (citing Mexican attorney’s testimony that “patria potestas
is the most sacred concept in Mexican family law”). Galvan
maintains that article 416 overrides the default rule in the case
of unmarried, noncohabiting parents. But we reject the idea
that the Code would exclude a subset of parents from such a
fundamental right in this backhanded manner.
    Galvan’s interpretation of article 416 has the further dis-
advantage of creating a gap in the law: no one would have
patria potestas over a child born to unmarried noncohabiting
parents. Even Galvan accepts that article 416 does not award
patria potestas to unmarried, noncohabiting parents; nor do ar-
ticles 380 and 381. The latter articles describe only how to
award physical custody, not patria potestas, for unmarried,
noncohabiting parents. Here and elsewhere the Code care-
fully distinguishes between patria potestas and custody. See
CCNL art. 415 bis (“Even if they do not have custody of the
minors, those exerting parental responsibility (patria potestas),
have a right to coexist (spend time) with their descendants
… .”). Galvan’s view, taken to its logical extreme, would pro-
duce the odd result that even she would not possess patria
potestas over D.S. today—indeed, no one would. This would
be inconsistent with article 412, which dictates that “non-
emancipated minors are under parental authority/responsi-
bility (patria potestas) as long as the ancestors that must exert
it according to the Law subsist.” Galvan’s response is to shift
her attention to the 2006 custody agreement as the source of
16                                                     No. 15-2983

her own patria potestas. We turn to that agreement in a mo-
ment. For now, we conclude that under the law of Nuevo
León, patria potestas attaches automatically at birth or ac-
knowledgment. Since at least 2006, Salazar has been D.S.’s
acknowledged father; he thus has the patria potestas right over
D.S. unless something in the 2006 agreement requires a differ-
ent result.
                                   2
    Putting original rights to one side, Galvan urges that the
2006 agreement not only clarified (or conferred) her sole phys-
ical custody rights, but also granted patria potestas to her ex-
clusively. In doing so, she says, it necessarily terminated any
original patria potestas right Salazar had; it did so by failing to
mention them.
    Some courts have held that patria potestas may be extin-
guished by a custody agreement. See, e.g., Gonzalez v.
Gutierrez, 311 F.3d 942, 954 (9th Cir. 2002) (“Here, unlike the
situation in Whallon, the parties have executed a formal, legal
custody agreement, thus eliminating any basis for relying on
patria potestas.”), abrogated by Abbott, 560 U.S. at 10, 22; see also
Avila, 538 F.3d at 587. None of these decisions, however, cites
any Mexican law for this proposition, nor do we find any ba-
sis for it in the Civil Code for Nuevo León. Even if they are
correct, however, the question would remain whether the
2006 agreement before us had that effect.
    Chapter III of the CCNL spells out the conditions under
which patria potestas may be suspended or terminated. The list
is extensive, detailed, and specific. The conditions all relate to
the parent’s ability or willingness to care for the child. See
CCNL arts. 443–448. Patria potestas terminates automatically
No. 15-2983                                                      17

only by the death of the person exercising it, the child’s eman-
cipation by marriage, or the child’s reaching majority. See
CCNL art. 443. The right can be terminated if the person exer-
cising it (1) is convicted of two or more serious crimes endan-
gering the child or the child’s assets, (2) is convicted of an in-
tentional offense against the child or the child’s assets, (3) mis-
treats or abandons the child in a way that puts the child at
risk, (4) fails to visit the child in a public welfare institution,
(5) abandons the child for greater than 180 days, or (6) leaves
the child alone for more than 30 days without any information
about the child’s origin. Id. art. 444. It can also be terminated
if the person exercising it “is expressly condemned to its loss.”
Id. It can be suspended for lack of capacity, formally declared
absence, or a criminal sentence imposing suspension. Id. art.
447. Article 447 bis notes that the patria potestas right may be
limited judicially, but the sole justification listed is “to protect
the physical or psychological integrity” of the child. Id. art.
447 bis.
    Neither a custody agreement nor anything akin to one is
listed as a condition that may terminate, suspend, or even
limit patria potestas. Nor is there a general provision for the
judicial surrender of parental authority and responsibility. To
the contrary, article 448 states expressly that “[p]arental au-
thority/responsibility [patria potestas] is not waivable.” Article
448 enumerates only two circumstances under which a person
with patria potestas may be excused of his or her duties: (1) if
the person is “sixty years or older” or (2) if he or she is “unable
to properly carry out [his or her] duties” because of “a state of
regular poor health.” Id. The fact that article 415 distinguishes
between custody and parental authority rights further but-
tresses the idea that patria potestas cannot be lost through a
custody agreement. Even if it were theoretically possible for a
18                                                 No. 15-2983

parent to lose patria potestas through a custody agreement, this
custody agreement would not suffice. Article 444’s sole sub-
section not conditioning termination on a specific contin-
gency indicates that a person may lose the patria potestas right
by being “expressly condemned to its loss.” The 2006 custody
agreement did not mention either Galvan or Salazar’s patria
potestas right, let alone “expressly condemn” Salazar to its
loss. The custody agreement thus did not extinguish Salazar’s
patria potestas right over D.S.
                               C
    As we noted earlier, patria potestas is considered a custo-
dial right for purposes of the Convention. Since Salazar has
that right, and Galvan arranged to have D.S. kept in the
United States against Salazar’s will, it follows that for Con-
vention purposes D.S. was wrongfully retained. This conclu-
sion, however, does not end our inquiry. Under the Conven-
tion, the district court had the discretion to refuse to return
D.S. to Mexico if Galvan proved by a preponderance of the
evidence that D.S. “object[ed] to being returned and ha[d] at-
tained an age and degree of maturity at which it is appropri-
ate to take account of [his] views.” Hague Convention art. 13,
T.I.A.S. No. 11670 (mature-child exception); 22 U.S.C.
§ 9003(e)(2)(B) (burden of proof for article 13 defenses). The
district court found that D.S. was sufficiently mature to in-
voke the exception, and we see nothing in the record to cast
doubt on that assessment. The district court also found that
D.S. eventually stated his objection to being returned to Mex-
ico during the second in-camera hearing. Both formal prereq-
uisites for this exception are therefore satisfied.
No. 15-2983                                                   19

    The question remains, however, whether the exception au-
tomatically applies in such a case, or if the district court re-
tains discretion to follow the rule rather than the exception. In
our view, it would be inconsistent both with the Convention
and with the often sensitive questions involved in domestic
relations to take a mechanical approach. This is consistent
with the way other courts and the U.S. Department of State
have understood the exceptions. They have said that a district
court retains discretion not to apply an exception, and that its
decision either way is reviewed only for abuse of discretion.
See de Silva v. Pitts, 481 F.3d 1279, 1285 (10th Cir. 2007) (“[A]
court still has discretion to order the return of the child if it
would further the aim of the Convention which is to provide
for the return of a wrongfully removed child.”) (citing Frie-
drich, 78 F.3d at 1067); England, 234 F.3d at 270–71; see also
Hague Convention art. 13, T.I.A.S. No. 11670 (“The judicial or
administrative authority may also refuse to order the return of
the child” if the mature-child exception applies) (emphasis
added); U.S. Dep’t of State Public Notice 957: Hague Int’l
Child Abduction Convention, 51 Fed. Reg. 10494, 10509 (1986)
(“The courts retain the discretion to order the child returned
even if they consider that one or more of the exceptions ap-
plies.”).
    Here, the district court decided that it would be incon-
sistent with the aims of the Convention to refuse to repatriate
D.S. First, it noted D.S.’s ambivalence before he finally ob-
jected to returning to Mexico, and the fact that D.S.’s objection
was founded “almost entirely” on his belief that his mother
would not be able to travel to and from Mexico because of her
immigration status. Galvan observes, correctly, that D.S. gave
other reasons, too, but the district court’s sense of which rea-
20                                                               No. 15-2983

son predominated was not clear error. The court was particu-
larly struck by the fact that D.S. stated that he would not ob-
ject to return if his mother’s travel to and from Mexico were
not impeded, based on the assumption that she could obtain
the proper visa within six months. 1 The court never asked
D.S. how he would react to periods longer than six months.
    While this omission troubles us, in the end it does not com-
pel a finding that the district court abused its discretion. The
court’s greatest concern was independent of the amount of
time D.S. might go without seeing his mother. It believed that
the application of the mature-child exception in this case
would reward Galvan for problems of her own making. Her
immigration status was unstable because she (and D.S.) over-
stayed their tourist visas. It reasoned that allowing D.S. to stay
in the United States would allow Galvan to benefit from her
own violations of the Convention and U.S. immigration laws.


     1 The record is unclear both on the status of Galvan’s application for
legal permanent resident status and on the accuracy of the six-month esti-
mate. Apparently Galvan had been trying ever since her arrival in the
United States to pursue a visa, but she represents that she could not afford
the necessary fees. The process takes some time: a qualified person (such
as her husband) must first submit a Petition for Alien Relative (an I-130)
on her behalf. The alien must also submit an application for adjustment of
status (I-485). Although U.S. Citizenship and Immigration Services indi-
cates that the entire process can take as little as seven months, see USCIS
Processing Time Information, https://egov.uscis.gov/cris/process-
TimesDisplayInit.do (last updated Dec. 15, 2015) (choose “Chicago IL”
from “Field Office” drop-down menu), the Department of State represents
that “[t]he length of time [for processing] varies from case to case and can-
not be predicted for individual cases with any accuracy.” Bureau of Con-
sular Affairs, U.S. Dep’t of State, Immigrant Visa for a Spouse of a U.S. Citizen
(IR1 or CR1), http://travel.state.gov/content/visas/en/immigrate/fam-
ily/immediate-relative.html#13 (last visited Dec. 16, 2015).
No. 15-2983                                                   21

    Galvan argues that applying the mature-child exception
would not “reward” her for her immigration problems be-
cause her visa overstay was not a “strategic ploy” and the vi-
sas expired before the wrongful retention. She notes that even
the district court recognized that her conduct was not in bad
faith. The court’s rationale, she urges, fits only more egregious
cases of child abduction.
    Article 13 is meant to address both systemic concerns—in
particular, deterrence—and individual cases. See England, 234
F.3d at 271 (“The Convention’s primary aims are to ‘restore
the pre-abduction status quo and to deter parents from cross-
ing borders in search of a more sympathetic court.’”) (quoting
Friedrich, 78 F.3d at 1063); Explanatory Report ¶¶ 16 (noting
that one of the Convention’s two central objectives is “deter-
ring” the abductor by “depriv[ing] his actions of any practical
or juridical consequences”), 17 (noting the enforcement of the
objective of “effective respect for rights of custody and of ac-
cess ... belongs on the preventive level”), at 429–30. The dis-
trict court was concerned that exercising the exception in this
case would set a precedent that allows a parent to prevent the
return of a child by problems of his or her own making. It rea-
soned that an inquiry into a litigant’s subjective intentions is
a difficult endeavor, and one potentially subject to abuse by
savvy litigants. It would be difficult for a court to smoke out
bad faith in these situations. Neither the Convention nor
ICARA forbids the district court to take these concerns into
account when it makes its ultimate decision. The Conven-
tion’s “defenses … are narrowly construed” at least in part to
preserve that deterrence. De Silva, 481 F.3d at 1285.
    The district court also reasoned that this was a weak case
for the mature-child exception because D.S.’s objection was
22                                                   No. 15-2983

partially premised on getting “used” to missing his father and
extended family in Mexico, and D.S.’s views had not been
consistent. At the time of the wrongful retention in July 2014,
D.S. wanted to return to Mexico. By the time of the first in-
camera hearing, he preferred to stay in Chicago, but did not
object to being returned to Mexico. It was only at the second
in-camera hearing—roughly 13 months after he was wrong-
fully retained—that D.S. unequivocally objected to being re-
turned. The district court reasoned that refusing to return D.S.
under such conditions would reward Galvan for the contin-
ued wrongful retention. It would also signal that a parent
might escape the Convention by running out the clock until
the wrongfully retained child became accustomed to her new
home. See, e.g., Yang v. Tsui, 499 F.3d 259, 280 (3rd Cir. 2007)
(affirming district court’s decision not to exercise exception
because where the child “grew attached to her family and
life” in the place where she was wrongfully retained during
the retention itself, applying the exception “would encourage
parents to wrongfully retain a child for as long as possible[,]
… and reward [the retaining parent] for violating [the peti-
tioner’s] custody rights, and defeat the purposes of the Con-
vention”). The Convention is intended “to secure the prompt
return of children wrongfully removed to or retained in any
Contracting State.” Hague Convention art. 1, T.I.A.S. No.
11670 (emphasis added). Creating an incentive for delay
would frustrate this central purpose.
                               III
    There is no doubt that this is a close case. Two points, how-
ever, are clear: Salazar had patria potestas over D.S. at the time
of the retention; and he had “rights of custody” recognized by
No. 15-2983                                                 23

the Convention. That is enough to establish Galvan’s reten-
tion of D.S. in violation of her agreement with Salazar as
wrongful under the Convention. Whether to apply the ma-
ture-child exception was a question within the district court’s
discretion. We see nothing powerful enough in this record to
warrant the rejection of its conclusion, and so we AFFIRM its
judgment in favor of Salazar.
