What is the test for ineffective assistance in criminal law?

" 'A convicted defendant's claim that counsel's assistance was so defective as to require reversal of a conviction... has two components.' [Citations.] 'First, the defendant must show that counsel's performance was deficient.' [Citations.] Specifically, he must establish that 'counsel's representation fell below an objective standard of reasonableness... under prevailing professional norms.' [Citations.]" (People v. Ledesma (1987) 43 Cal.3d 171, 216.) "In addition to showing that counsel's performance was deficient, a criminal defendant must also establish prejudice before he can obtain relief on an ineffective-assistance claim." (Id. at p. 217.) Moreover, on appeal, if the record sheds no light on why counsel failed to act in the manner challenged, unless counsel was asked for an explanation and failed to provide one, or unless there simply could be no satisfactory explanation, an ineffective assistance contention must be rejected. (People v. Slaughter (2002) 27 Cal.4th 1187, 1219.)

In Gant, after the defendant was arrested for driving with a suspended license, handcuffed, and locked in the back of a patrol car, police searched his car and discovered cocaine in the pocket of a jacket on the backseat. Because the defendant could not have accessed his car to retrieve weapons or evidence at the time of the search, the high court concluded that the search-incident-to-arrest exception to the Fourth Amendment's warrant requirement, as defined in Chimel v. California (1969) 395 U.S. 752 [89 S.Ct. 2034], and applied to vehicle searches in New York v. Belton (1981) 453 U.S. 454 [101 S.Ct. 2860], did not justify the search in Gant. (Gant, supra, 129 S.Ct. at p. 1714.)

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