California v. Trombetta/Concurrence O'Connor

, concurring.

Rules concerning preservation of evidence are generally matters of state, not federal constitutional law. See United States v. Augenblick, 393 U.S. 348, 352–353 (1969). The failure to preserve breath samples does not render a prosecution fundamentally unfair, and thus cannot render breath-analysis tests inadmissible as evidence against the accused. Id., at 356. Similarly, the failure to employ alternative methods of testing blood-alcohol concentrations is of no due [p492] process concern, both because persons are presumed to know their rights under the law and because the existence of tests not used in no way affects the fundamental fairness of the convictions actually obtained. I understand the Court to state no more than these well-settled propositions. Accordingly, I join both its opinion and judgment.