CA10: Mistake of law on applicability of a traffic law is an objectively unreasonable stop.

Mistake of law on applicability of a traffic law is an objectively unreasonable stop. Three guns suppressed. United States v. Nicholson, 721 F.3d 1236 (10th Cir. 2013):

The government insists we should nonetheless uphold the stop because the law which served as the basis for Officer Baker’s stop is not “plain and unambiguous.” Even assuming the law was unclear, we cannot agree. In our circuit, as in most others, mistakes of law made by an officer are objectively unreasonable. See Tibbets, 396 F.3d at 1138; see also United States v. McDonald, 453 F.3d 958, 960-62 (7th Cir. 2006) (officer lacked probable cause to stop defendant based on mistaken belief defendant violated law by using his left-turn signal while going around a bend); United States v. Chanthasouxat, 342 F.3d 1271, 1278-80 (11th Cir. 2003) (held a mistake of law invalidated a traffic stop even though the officer believed the law existed based on training, guidance from a magistrate, and the more than 100 tickets he had written citing it); United States v. Lopez-Soto, 205 F.3d 1101, 1106-07 (9th Cir. 2000) (officer lacked reasonable suspicion to stop defendant based on mistaken belief about proper placement of registration sticker); United States v. Miller, 146 F.3d 274, 277-79 (5th Cir. 1998) (officer lacked probable cause to stop defendant based on mistaken belief defendant violated law by using turn signal without changing lanes or turning); but see United States v. Washington, 455 F.3d 824, 827 (8th Cir. 2006) (instead looking at whether a mistake of law is “objectively reasonable”).

As we said in Tibbetts,”failure to understand the law by the very person charged with enforcing it is not objectively reasonable.” 396 F.3d 1132 at 1136. See also Sherouse v. Ratchner, 573 F.3d 1055, 1059 (10th Cir. 2009) (“While an officer’s reasonable but mistaken understanding of the facts justifying a search or seizure does not negate the legitimacy of a probable cause determination, an officer’s reasonable but mistaken understanding of the applicable law he is enforcing does.”). Nothing in our opinion in Tibbetts suggests we actually meant to limit this rule only to the mistaken understanding of “plain and unambiguous laws.” In providing the district court with guidance for interpreting the Utah statute at issue we said that “Utah courts look to the plain language of the statute, and only when the language is ambiguous do they seek guidance from legislative history or policy considerations.” Id. at 1138. This instruction on ambiguity seems unnecessary if we only fault police officers when a law is plain and unambiguous.

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