It is likely that the cases posing the greatest difficulty are those in which the procedural defects of the foreign trial leave an American court in doubt about the prisoner's guilt, especially if the resulting sentence is long. Lack of effective counsel, use of coerced confessions, and the absence of a speedy trial are the principal problem areas. Some inquiries should be made to aid in estimating the number of serious constitutional claims likely to be advanced under such treaties. Although the apparent intent of the treaties is to foreclose the returned prisoners from collaterally challenging their foreign sentences, the issue is whether an American citizen must waive his/her rights guaranteed under the Constitution in order to serve his/her sentence in the American correctional system. If the treaty does hope to avoid constitutional issues under the view that participation in the benefits of the treaty involves the waiver of such rights, then that waiver in itself becomes a constitutional issue. Judicial decisions bearing upon the treaties' legal status are discussed. Footnotes are provided.