In the case of Marshall, Superintendent, Southern Ohio Correctional Facility v. Lonberger in 1982, the US Supreme Court ruled on whether a defendant's guilty plea could be used as evidence against him in a later trial for another crime. The court held that it was not unconstitutional to use such pleas if they were made voluntarily and intelligently. In this case, respondent Lonberger had pleaded guilty to burglary charges years earlier and his confession was used against him during his murder trial. He argued that he did not fully understand the consequences of his plea at the time he made it because he wasn't represented by counsel when entering his plea and therefore should have been considered involuntary under Boykin v Alabama (1969). However, after reviewing records from both trials including transcripts showing Lonberger acknowledged understanding what pleading guilty meant along with its potential implications before making said plea; SCOTUS disagreed with Lonberger’s argument stating there is no constitutional requirement for explicit advice about all possible consequences before accepting a guilty plea.

In the dissenting opinion for Marshall v. Lonberger, Justice Brennan disagreed with the majority's decision to uphold Lonberger's conviction based on a prior guilty plea. He argued that there was insufficient evidence to prove beyond a reasonable doubt that Lonberger fully understood his rights when he pleaded guilty in an earlier trial. The only proof of this understanding was a form signed by Lonberger stating he had been informed of his rights; however, Brennan pointed out that signing such forms is often routine and does not necessarily indicate full comprehension or voluntary waiver of one’s rights. Furthermore, no transcript existed from the original court proceedings to confirm whether proper protocol was followed during the plea process. Therefore, according to Brennan, it could not be definitively concluded that Lonberger knowingly waived his constitutional right against self-incrimination at the time of his initial guilty plea.