The clause provides that no person can be convicted twice of the same offense. Its basic concept is found in English common law, although some scholars suggest that the idea has its origins in Roman law. The effectiveness of the clause depends on whether two separate offenses can be considered to be the same offense. In addition, the defendant's relinquishment of a double jeopardy claim can be an issue. Thus, in the 1989 decision in United States v. Broce, the United States Supreme Court held unanimously that the defendant could not assert a double jeopardy claim because he had waived it in the plea bargain agreement. The Broce decision may signal a new movement toward narrowing the defendant's right to a claim of double jeopardy. In future decisions, courts should include in their inquiry about whether a waiver is knowing and intentional an investigation of whether the defendant understands that waiving the right to trial as part of a plea agreement is also waiving the double jeopardy claim. 127 footnotes.