In People v. Catalanotte (72 NY2d 641 [1988]), the Court of Appeals established a two-pronged standard for determining the viability of a challenge, in a predicate sentencing proceeding, of a defendant's prior felony conviction as retrospectively violative of a federal constitutional rule. To qualify as applicable for such use, the Court of Appeals there announced, the federal constitutional rule must either be "the law existing at the time the conviction was obtained," or, alternatively, it must be "subsequent law applicable to the judgment under principles of retroactivity." (Id. at 645.)