The US Court of Appeals for the Federal Circuit's infamous Festo decision has led to countless debates as to how careful one should now be when amending the claims of US patent applications during prosecution before the USPTO. The US Supreme Court, in its judgment rendered in May 2002, has partially softened the harsh impact of the CAFC's original decision, which applied a file wrapper estoppel completely barring the use of the doctrine of equivalents in subsequent infringement proceedings as far as the amended portion of the claim was concerned.