                    FOR PUBLICATION

   UNITED STATES COURT OF APPEALS
        FOR THE NINTH CIRCUIT


 UNITED STATES OF AMERICA,                        No. 17-50384
                  Plaintiff-Appellee,
                                                    D.C. No.
                     v.                          2:16-cr-00681-
                                                     FMO-1
 JORGE GUERRERO, AKA Benji, AKA
 Dreamer, AKA Ricardo Guerrero,
 AKA Lil Dreamer,                                   OPINION
              Defendant-Appellant.



        Appeal from the United States District Court
            for the Central District of California
       Fernando M. Olguin, District Judge, Presiding

           Argued and Submitted January 10, 2019
                    Pasadena, California

                      Filed April 22, 2019

 Before: A. Wallace Tashima and Paul J. Watford, Circuit
    Judges, and Eduardo C. Robreno, * District Judge.

                      Per Curiam Opinion


     *
       The Honorable Eduardo C. Robreno, United States District Judge
for the Eastern District of Pennsylvania, sitting by designation.
2                UNITED STATES V. GUERRERO

                          SUMMARY **


                          Criminal Law

    The panel affirmed the district court’s denial of a motion
to suppress a gun and ammunition found during a traffic
stop.

    The panel held that in the wake of the 2014 amendments
to Fed. R. Crim. P. 12, the good-cause standard in Fed. R.
Crim. P. 12(c)(3), rather than plain error review, continues
to apply when a defendant attempts to raise new theories on
appeal in support of a motion to suppress. The panel held
that the defendant did not show good cause for failing to
present in his pre-trial motion the new theory he raised in
this appeal.


                            COUNSEL

Gia Kim (argued), Deputy Federal Public Defender; Hilary
Potashner, Federal Public Defender; Office of the Federal
Public Defender, Los Angeles, California; for Defendant-
Appellant.

Michael Gregory Freedman (argued), Assistant United
States Attorney; Lawrence S. Middleton, Chief, Criminal
Division; Nicola T. Hanna, United States Attorney; United
States Attorney’s Office, Los Angeles, California; for
Plaintiff-Appellee.


    **
       This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
               UNITED STATES V. GUERRERO                     3

                         OPINION

PER CURIAM:

    Jorge Guerrero challenges the denial of his motion to
suppress a gun and ammunition found during a traffic stop.
Guerrero was a passenger in a car that the police pulled over
after they allegedly observed the driver fail to signal before
making a left turn. In the district court, Guerrero raised a
single argument in support of his motion: that the officers
lacked reasonable suspicion to make the stop because the
driver had in fact signaled in advance of her turn. The
district court held an evidentiary hearing at which Guerrero,
the driver, and the officers testified. The court found the
officers’ testimony more credible and held that the driver’s
failure to signal provided a lawful basis for the stop.
Following the denial of his motion to suppress, Guerrero
entered a conditional guilty plea to being a felon in
possession of a firearm and ammunition. 18 U.S.C.
§ 922(g)(1).

    On appeal, Guerrero presents a new theory in support of
his motion to suppress. He notes that California law requires
a driver to signal before making a turn only if another vehicle
on the road “may be affected by the movement.” Cal.
Vehicle Code § 22107; see People v. Carmona, 124 Cal.
Rptr. 3d 819, 823–25 (Ct. App. 2011). He asserts that the
government introduced insufficient evidence that the
driver’s alleged failure to signal could have impacted
another car on the road. See United States v. Caseres,
533 F.3d 1064, 1069 (9th Cir. 2008). Thus, he concludes,
even if the driver did not signal before turning, the officers
lacked a lawful basis for making the stop. The crucial fact
for our purposes is that Guerrero never requested
suppression on this ground in the district court.
4              UNITED STATES V. GUERRERO

    We have decided to publish in this case to clarify the
standard of review that governs in the wake of the 2014
amendments to Federal Rule of Criminal Procedure 12. That
rule requires certain “defenses, objections, and requests”—
including a request for suppression of evidence—to be raised
by pre-trial motion. Fed. R. Crim. P. 12(b)(3)(C). Before
2014, Rule 12 directed that a party “waives” any
Rule 12(b)(3) defense, objection, or request not asserted in a
pre-trial motion, but also provided that, “[f]or good cause,
the court may grant relief from the waiver.” Fed. R. Crim.
P. 12(e) (2003). We interpreted this provision to mean that
“[a] theory for suppression not advanced in district court
cannot be raised for the first time on appeal” absent a
showing of good cause. United States v. Keesee, 358 F.3d
1217, 1220 (9th Cir. 2004); see also United States v.
Restrepo-Rua, 815 F.2d 1327, 1329 (9th Cir. 1987) (per
curiam). We thus construed Rule 12’s good-cause standard
as displacing the plain-error standard under Federal Rule of
Criminal Procedure 52(b), which ordinarily applies when a
party presents an issue for the first time on appeal. See
United States v. Wright, 215 F.3d 1020, 1026–27 (9th Cir.
2000).

    In 2014, the text of Rule 12(e) was amended and moved
to subsection (c)(3).       Rule 12 now specifies the
consequences of failing to make a timely motion in these
terms:

           (3) Consequences of Not Making a
       Timely Motion Under Rule 12(b)(3). If a
       party does not meet the deadline for making
       a Rule 12(b)(3) motion, the motion is
       untimely. But a court may consider the
       defense, objection, or request if the party
       shows good cause.
               UNITED STATES V. GUERRERO                     5

Fed. R. Crim. P. 12(c)(3).

    Since the 2014 amendments, our sister circuits have
reached conflicting conclusions on the standard of review
that should apply in this context. Three circuits have held
that untimely Rule 12(b)(3) defenses, objections, and
requests raised for the first time on appeal should be
reviewed for plain error under Rule 52(b). United States v.
Vasquez, 899 F.3d 363, 372–73 (5th Cir. 2018); United
States v. Sperrazza, 804 F.3d 1113, 1119 (11th Cir. 2015);
United States v. Soto, 794 F.3d 635, 654–55 (6th Cir. 2015).
The other circuits to decide the issue continue to apply
Rule 12(c)(3)’s good-cause standard instead. United States
v. Vance, 893 F.3d 763, 769–70 & n.5 (10th Cir. 2018);
United States v. Walker-Couvertier, 860 F.3d 1, 9 & n.1
(1st Cir. 2017); United States v. Fattah, 858 F.3d 801, 807
(3d Cir. 2017); United States v. McMillian, 786 F.3d 630,
636 & n.3 (7th Cir. 2015); United States v. Anderson,
783 F.3d 727, 741 (8th Cir. 2015); see also United States v.
Burroughs, 810 F.3d 833, 838 (D.C. Cir. 2016)
(acknowledging the split without choosing a side).

    Guerrero contends that we should align ourselves with
the circuits that review untimely defenses, objections, and
requests for plain error. Were we writing on a blank slate,
we might have been inclined to follow their lead. Plain-error
review under Rule 52(b) is the default standard governing
our consideration of issues not properly raised in the district
court, and the Supreme Court has set a high bar for creating
exceptions to that standard. See Puckett v. United States,
556 U.S. 129, 135–36 (2009); Johnson v. United States,
520 U.S. 461, 466 (1997). Appellate courts are also familiar
with the elements required to show plain error under
Rule 52(b), as we are called upon to apply that standard in a
wide range of settings. In contrast, we are less well-versed
6              UNITED STATES V. GUERRERO

in applying Rule 12’s good-cause standard, which “often
requires developing and analyzing facts to determine
whether a defendant has shown good cause for the late
filing.” Soto, 794 F.3d at 655.

    Nevertheless, as a three-judge panel, we may not forge
our own path unless our prior precedent “is clearly
irreconcilable with the text and history of subsequent
legislation” or rulemaking. United States v. Pepe, 895 F.3d
679, 686 (9th Cir. 2018). That demanding standard has not
been met here. As Guerrero points out, Rule 12 no longer
labels untimely defenses, objections, and requests as
“waived.” But the 2014 amendments to Rule 12 did not
eliminate the good-cause standard. Nor did they clarify that
appellate courts should apply Rule 52(b)’s plain-error
standard instead of the good-cause standard. In fact, the
rulemaking history indicates that the Advisory Committee
chose not to take a position on which of the two standards
should apply, leaving that matter for the circuit courts to
decide: “The amended rule, like the current one, continues
to make no reference to Rule 52 (providing for plain error
review of defaulted claims), thereby permitting the Courts of
Appeals to decide if and how to apply Rules 12 and 52 when
arguments that should have been the subject of required
Rule 12(b)(3) motions are raised for the first time on
appeal.” Report of the Advisory Committee on Federal
Rules of Criminal Procedure to the Standing Committee on
Rules of Practice and Procedure 5–6 (May 2013).
Accordingly, we cannot say that our prior precedent is
clearly irreconcilable with the amended version of Rule 12.

    Rule 12(c)(3)’s good-cause standard continues to apply
when, as in this case, the defendant attempts to raise new
theories on appeal in support of a motion to suppress.
Guerrero has not shown good cause for failing to present in
               UNITED STATES V. GUERRERO                   7

his pre-trial motion the new theory for suppression he raises
in this appeal. Nor has he challenged the district court’s
rejection of the one theory that he did raise below. We
therefore affirm the district court’s denial of his motion to
suppress.

   AFFIRMED.
