SD: Objectively unreasonable mistakes of law do not support arrests

Noting a conflict in the cases, with the majority of cases saying a mistake of law is not objective good faith, South Dakota decides that objectively unreasonable mistakes of law do not support arrests. State v. Wright, 2010 SD 91, 791 N.W.2d 791 (December 8, 2010):

[*P21] This case is thus more analogous to Webb and Washington than Martin. Trooper Biehl may have believed in good faith that Wright violated SDCL 32-17-7, “[b]ut his subjective good faith is not sufficient to justify the stop[.]” Martin, 411 F.3d at 1001. “[O]fficers have an obligation to understand the laws that they are entrusted with enforcing, at least to a level that is objectively reasonable.” Id. “Any mistake of law that results in a search or seizure, therefore, must be objectively reasonable to avoid running afoul of the Fourth Amendment.” Id. Trooper Biehl acted upon a mistake concerning a clear and unambiguous statute. Given the clear and unambiguous language of SDCL 32-17-7, Trooper Biehl’s mistake of law was not objectively reasonable. Consequently, the trial court erred by denying Wright’s motion to suppress the evidence discovered during the stop and subsequent search of his vehicle.

The fact the officer arrested defendant with probable cause but contrary to a Sheriff’s directive or in violation of statute was not a Fourth Amendment issue. State v. Talbot, 2010 UT App 352, 246 P.3d 112, 671 Utah Adv. Rep. 12 (2010):

[*P10] For purposes of this appeal, we accept Talbot’s assertion that the Deputy’s initial encounter with Talbot was an arrest rather than a detention. Talbot makes no claim that the Deputy’s inherent authority as a serving peace officer to arrest malefactors was constrained by anything other than the Sheriff’s instructions and constitutional boundaries. Applying the reasoning of Harker, we conclude that so long as Talbot’s arrest was justified by probable cause, the fact that the Deputy may have exceeded the instructions given to him by the Sheriff has no bearing on whether Talbot’s arrest was “lawful” under the Constitution. If an arrest in violation of a statutory restriction does not itself raise constitutional issues, then, a fortiori, an arrest that exceeds a superior’s immediate directive in a particular circumstance does not do so. Therefore, the pivotal question in determining whether Talbot’s arrest was constitutional is whether the arrest was supported by probable cause.