 He also offered to stipulate to the fact that he had suffered a prior conviction that made him a prohibited possessor.The reason for asking the prosecution not to mention the facts of the prior crime, he said, was to preserve his right to be convicted by a jury beyond a reasonable doubt on the basis of the facts relating to only the conduct with which he was currently charged.In light of the stipulation, he contended that introducing any evidence relating to the facts of his prior crimes would be unfairly prejudicial under Rule 403 of the Federal Rules of Evidence.