Findings of fact are reviewed for clear error. See Mull for Mull v. Motion Picture Indus. Health Plan, 865 F.3d 1207, 1209 (9th Cir. 2017); L.J. by & through Hudson v. Pittsburg Unified Sch. Dist., 850 F.3d 996, 1002 (9th Cir. 2017) (noting standard applies even when findings are based on the administrative record); Stetson v. Grissom, 821 F.3d 1157, 1163 (9th Cir. 2016); Husain v. Olympic Airways, 316 F.3d 829, 835 (9th Cir. 2002). This standard also applies to the district court’s application of law to facts where it requires an “essentially factual” review. See Hussein, 316 F.3d at 835. The court reviews adopted findings with close scrutiny, even though review remains to be for clear error. See Phoenix Eng’g & Supply Inc. v. Universal Elec. Co., 104 F.3d 1137, 1140 (9th Cir. 1997).
Conclusions of law are reviewed de novo. See Mull for Mull, 865 F.3d at 1209; Stetson, 821 F.3d at 1163; Husain, 316 F.3d at 835. Mixed questions of law and fact are also reviewed de novo. See Lim v. City of Long Beach, 217 F.3d 1050, 1054 (9th Cir. 2000). A mixed question of law and fact exists when there is no dispute as to the facts or the rule of law and the only question is whether the facts satisfy the legal rule. See id.; see also In re Cherrett, 873 F.3d 1060, 1066 (9th Cir. 2017). “ ‘Mixed questions are typically reviewed de novo, but, depending on the nature of the inquiry involved, may be reviewed under a more deferential clearly erroneous standard.’ United States v. Lang, 149 F.3d 1044, 1047 (9th Cir. 1998), amended by 157 F.3d 1161 (9th Cir. 1998) (emphasis added).” In re Cherrett, 873 F.3d at 1066.
A district court’s interpretation of the Federal Rules of Civil Procedure is reviewed de novo. See United States v. 2,164 Watches, 366 F.3d 767, 770 (9th Cir. 2004).
The district court’s decision may be affirmed on any ground supported by the record, even if not relied upon by the district court. See Cassirer v. Thyssen-Bornemisza Collection Found., 862 F.3d 951, 974 (9th Cir. 2017); Kwan v. SanMedica Int'l, 854 F.3d 1088, 1093 (9th Cir. 2017); Campbell v. Washington Dep’t of Soc. & Health Servs., 671 F.3d 837, 842 n.4 (9th Cir. 2011); Forest Guardians v. U.S. Forest Serv., 329 F.3d 1089, 1097 (9th Cir. 2003). Accordingly, the decision may be affirmed, “even if the district court relied on the wrong grounds or wrong reasoning.” Cigna Property and Cas. Ins. Co. v. Polaris Pictures Corp., 159 F.3d 412, 418 (9th Cir. 1998) (citation omitted); see also Muniz v. United Parcel Serv., Inc., 738 F.3d 214, 219 (9th Cir. 2013).
Whether a public official is entitled to absolute immunity is a question of law reviewed de novo. See Brown v. California Dep’t of Corr., 554 F.3d 747, 749-50 (9th Cir. 2009); Miller v. Davis, 521 F.3d 1142, 1145 (9th Cir. 2008) (governor). A dismissal based on absolute immunity is reviewed de novo. See Garmon v. Cty. of Los Angeles, 828 F.3d 837, 842 (9th Cir. 2016); Olsen v. Idaho State Bd. of Medicine, 363 F.3d 916, 922 (9th Cir. 2004) (state board member).
This court reviews de novo whether Younger abstention is required. See Nationwide Biweekly Admin., Inc. v. Owen, 873 F.3d 716, 727 (9th Cir. 2017); Potrero Hills Landfill, Inc. v. County of Solano, 657 F.3d 876, 881 (9th Cir. 2011); Green v. City of Tucson, 255 F.3d 1086, 1093 (9th Cir. 2001) (en banc) (overruling prior cases applying abuse of discretion standard to district court’s decision whether to abstain), overruled in part on other grounds by Gilbertson v. Albright, 381 F.3d 965, 976-78 (9th Cir. 2004).
Note that Green may not apply to other abstention doctrines. See Green, 255 F.3d at 1093 n.10. For example, the court of appeals reviews Pullman abstention decisions under a “modified abuse of discretion standard.” Smelt v. County of Orange, 447 F.3d 673, 678 (9th Cir. 2006). This means the court reviews de novo whether the requirements have been met, but the district court’s ultimate decision to abstain under Pullman for abuse of discretion. See id.
“The proper standard of review for the district court’s decision to abstain under O’Shea is unsettled.” Courthouse News Serv. v. Planet, 750 F.3d 776, 782 (9th Cir. 2014) (declining to decide which standard of review applies).
“[A] district court’s decisions with regard to the treatment of affirmative defenses [are] reviewed for an abuse of discretion.” 389 Orange St. Part. v. Arnold, 179 F.3d 656, 664 (9th Cir. 1999); see also In re Hanford Nuclear Reservation Litig., 534 F.3d 986, 1000 (9th Cir. 2008) (reviewing de novo where defense inapplicable as matter of law). Whether an affirmative defense is waived, however, is a question of law reviewed de novo. See Owens v. Kaiser Found. Health Plan, Inc., 244 F.3d 708, 713 (9th Cir. 2001).
The district court’s decision to strike certain affirmative defenses pursuant to Rule 12(f) is reviewed for an abuse of discretion. See Federal Sav. & Loan Ins. Corp. v. Gemini Mgmt., 921 F.2d 241, 243-44 (9th Cir. 1990). Likewise, the decision whether to instruct the jury on affirmative defenses is reviewed for an abuse of discretion. See Costa v. Desert Palace, Inc., 299 F.3d 838, 858-59 (9th Cir. 2002) (en banc) (instructing); McClaran v. Plastic Indus., Inc., 97 F.3d 347, 355-56 (9th Cir. 1996) (refusing to instruct).
The trial court’s denial of a motion to amend a complaint is reviewed for an abuse of discretion. See Branch Banking & Tr. Co. v. D.M.S.I., LLC, 871 F.3d 751, 760 (9th Cir. 2017); AE ex rel. Hernandez v. County of Tulare, 666 F.3d 631, 636 (9th Cir. 2012); Ventress v. Japan Airlines, 603 F.3d 676, 680 (9th Cir. 2010); Caswell v. Calderon, 363 F.3d 832, 836 (9th Cir. 2004) (habeas); Chappel v. Laboratory Corp., 232 F.3d 719, 725 (9th Cir. 2000) (finding abuse of discretion). “A district court acts within its discretion to deny leave to amend when amendment would be futile, when it would cause undue prejudice to the defendant, or when it is sought in bad faith.” Chappel, 232 F.3d at 725-26. The discretion is particularly broad where a plaintiff has previously been permitted leave to amend. See Chodos v. West Publishing Co., 292 F.3d 992, 1003 (9th Cir. 2002).
The trial court’s decision to permit amendment is also reviewed for an abuse of discretion. See Metrophones Telecomms., Inc, v. Global Crossing Telecomms., Inc., 423 F.3d 1056, 1063 (9th Cir. 2005); United States v. McGee, 993 F.2d 184, 187 (9th Cir. 1993).
Dismissal of a complaint without leave to amend is improper unless it is clear, upon de novo review that the complaint could not be saved by any amendment. See AE ex rel. Hernandez, 666 F.3d at 636; Thinket Ink Info. Res., Inc. v. Sun Microsystems, Inc., 368 F.3d 1053, 1061 (9th Cir. 2004).
A district court’s order denying a Rule 15(b) motion to conform the pleadings to the evidence is reviewed for an abuse of discretion. See Rosenbaum v. City and County of San Francisco, 484 F.3d 1142, 1151 (9th Cir. 2007); Madeja v. Olympic Packers, 310 F.3d 628, 635 (9th Cir. 2002). The court’s decision to grant a Rule 15(b) motion is also reviewed for an abuse of discretion. See Galindo v. Stoody Co., 793 F.2d 1502, 1512-13 (9th Cir. 1986).
The district court’s dismissal of the complaint with prejudice for failure to comply with the court’s order to amend the complaint is reviewed for an abuse of discretion. See Ordonez v. Johnson, 254 F.3d 814, 815-16 (9th Cir. 2001); McHenry v. Renne, 84 F.3d 1172, 1177 (9th Cir. 1996). Dismissal of a complaint for failure to serve a timely summons and complaint is also reviewed for abuse of discretion. See In re Sheehan, 253 F.3d 507, 511 (9th Cir. 2001); West Coast Theater Corp. v. City of Portland, 897 F.2d 1519, 1528 (9th Cir. 1990).
A district court’s decision to grant or deny a party’s request to supplement a complaint pursuant to Fed. R. Civ. P. 15(d) is reviewed for an abuse of discretion. Planned Parenthood of S. Ariz. v. Neely, 130 F.3d 400, 402 (9th Cir. 1997) (per curiam); Keith v. Volpe, 858 F.2d 467, 473 (9th Cir. 1988).
See also III. Civil Proceedings, B. Pretrial Decisions in Civil Cases, 54. Leave to Amend.
A district court’s decision to permit a party to amend its answer is reviewed for an abuse of discretion. See C.F. ex rel. Farnan v. Capistrano Unified Sch. Dist., 654 F.3d 975, 985 (9th Cir. 2011); Waldrip v. Hall, 548 F.3d 729, 732 (9th Cir. 2008).
The court’s refusal to permit a defendant to amend pleadings to assert additional counterclaims in an answer is also reviewed for an abuse of discretion. See California Dep’t of Toxic Substances Control v. Neville Chem. Co., 358 F.3d 661, 673 (9th Cir. 2004). See also Branch Banking & Tr. Co. v. D.M.S.I., LLC, 871 F.3d 751, 764–65 (9th Cir. 2017) (no abuse of discretion in denying motion to amend answer to add four new defenses and a counterclaim).
The court’s decision to strike an answer and enter default judgment as a discovery sanction is reviewed for an abuse of discretion. See Fair Housing of Marin v. Combs, 285 F.3d 899, 905 (9th Cir. 2002).
“The decision to appoint counsel is left to the sound discretion of the district court.” Johnson v. United States Treasury Dep’t, 27 F.3d 415, 416‑17 (9th Cir. 1994) (per curiam) (employment discrimination) (listing factors for court to consider); see also Harrington v. Scribner, 785 F.3d 1299, 1309 (9th Cir. 2015). The trial court’s refusal to appoint counsel is reviewed for an abuse of discretion. See Harrington, 785 F.3d at 1309; Campbell v. Burt, 141 F.3d 927, 931 (9th Cir. 1998) (civil rights); see also Manley v. Rowley, 847 F.3d 705, 712 n.3 (9th Cir. 2017) (magistrate judge did not abuse his discretion by denying motion to appoint counsel). The trial court’s decision on a motion for appointment of counsel pursuant to 28 U.S.C. § 1915 is also reviewed for an abuse of discretion. See Solis v. County of Los Angeles,