The Post-Festo World of Equivalents, 2 J. Marshall Rev. Intell. Prop. L. 182 (2003)

The Supreme Court again began to delve into substantial patent issues by addressing the interplay between prosecution history estoppel and the doctrine of equivalents. An analysis of the opinions in the Federal Circuit’s en banc ruling, together with the Supreme Court’s own decision may help to clarify some of the unanswered questions still lingering regarding what equivalents are available and when. The prosecution history will take a more prominent place in the minds of both patent prosecutors and litigators as courts attempt to determine the appropriate relationship between prosecution history estoppel and the doctrine of equivalents.