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No. 10656728
United States Court of Appeals for the Ninth Circuit
United States v. Castillo-Pena
No. 10656728 · Decided August 19, 2025
No. 10656728·Ninth Circuit · 2025·
FlawFinder last updated this page Apr. 2, 2026
Case Details
Court
United States Court of Appeals for the Ninth Circuit
Decided
August 19, 2025
Citation
No. 10656728
Disposition
See opinion text.
Full Opinion
NOT FOR PUBLICATION FILED
UNITED STATES COURT OF APPEALS AUG 19 2025
MOLLY C. DWYER, CLERK
U.S. COURT OF APPEALS
FOR THE NINTH CIRCUIT
UNITED STATES OF AMERICA, No. 24-4257
D.C. No.
Plaintiff - Appellee, 2:20-cr-00590-RGK-1
v.
MEMORANDUM*
CESAR CASTILLO-PENA,
Defendant - Appellant.
Appeal from the United States District Court
for the Central District of California
R. Gary Klausner, District Judge, Presiding
Submitted August 15, 2025**
Pasadena, California
Before: NGUYEN, FORREST, and VANDYKE, Circuit Judges.
Cesar Castillo-Pena appeals the district court’s denial of his motion for a
sentence reduction under a retroactive amendment to the U.S. Sentencing
Guidelines. See 18 U.S.C. § 3582(c)(2); U.S. Sent’g Guidelines Manual
*
This disposition is not appropriate for publication and is not precedent
except as provided by Ninth Circuit Rule 36-3.
**
The panel unanimously concludes this case is suitable for decision
without oral argument. See Fed. R. App. P. 34(a)(2).
(“U.S.S.G.”) § 4C1.1(a) (U.S. Sent’g Comm’n 2021). Reviewing his preserved
claim for abuse of discretion, see United States v. Lizarraras-Chacon, 14 F.4th
961, 964–65 (9th Cir. 2021), and his unpreserved claims for plain error, see United
States v. Depue, 912 F.3d 1227, 1232 (9th Cir. 2019) (en banc), we affirm.
1. The district court did not plainly err by finding that Castillo-Pena failed
to show that he “did not possess . . . a firearm . . . in connection with the offense.”
U.S.S.G. § 4C1.1(a)(7). As part of the factual basis for his plea, Castillo-Pena
agreed that he possessed the firearm “as part of the planned transaction.” Even if,
as he argued to the district court, his possession was “consistent with self-defense,”
his possession was still “in connection with” the drug exchange regardless of
whether he possessed the gun for self-defense in other situations. See United
States v. Ferryman, 444 F.3d 1183, 1186 (9th Cir. 2006).
2. The district court’s failure to address Castillo-Pena’s Second Amendment
argument was harmless. Assuming that his conduct falls within the plain text of
the Second Amendment, there is “a history and tradition of regulating the
possession of firearms during the commission of felonies involving a risk of
violence,” and “drug trafficking plainly poses substantial risks of confrontation that
can lead to immediate violence.” United States v. Alaniz, 69 F.4th 1124, 1129–30
(9th Cir. 2023). The Guidelines’ increased sentencing exposure for possessing a
2 24-4257
firearm in connection with a drug offense does not violate the Second Amendment.
See id.
3. U.S.S.G. § 4C1.1(a)(7) does not plainly violate the Ex Post Facto Clause.
A retrospective decrease in the Guidelines range “poses no Ex Post Facto
concerns,” United States v. Bautista, 989 F.3d 698, 703 (9th Cir. 2021), because
there is “no constitutional requirement of retroactivity that entitles defendants
sentenced to a term of imprisonment to the benefit of subsequent Guidelines
amendments,” Dillon v. United States, 560 U.S. 817, 828 (2010).
AFFIRMED.
3 24-4257
Plain English Summary
NOT FOR PUBLICATION FILED UNITED STATES COURT OF APPEALS AUG 19 2025 MOLLY C.
Key Points
01NOT FOR PUBLICATION FILED UNITED STATES COURT OF APPEALS AUG 19 2025 MOLLY C.
02COURT OF APPEALS FOR THE NINTH CIRCUIT UNITED STATES OF AMERICA, No.
03Gary Klausner, District Judge, Presiding Submitted August 15, 2025** Pasadena, California Before: NGUYEN, FORREST, and VANDYKE, Circuit Judges.
04Cesar Castillo-Pena appeals the district court’s denial of his motion for a sentence reduction under a retroactive amendment to the U.S.
Frequently Asked Questions
NOT FOR PUBLICATION FILED UNITED STATES COURT OF APPEALS AUG 19 2025 MOLLY C.
FlawCheck shows no negative treatment for United States v. Castillo-Pena in the current circuit citation data.
This case was decided on August 19, 2025.
Use the citation No. 10656728 and verify it against the official reporter before filing.