The U.S. Supreme Court recently handed down a landmark decision of enormous import, which have United States inventors and patent attorneys feeling festive, or at least breathing a collective sigh of relief. In Festo v. Shoketsu, __ U.S. ___ (2002) (decided May 28, 2002), the Court vacated a judgment of the Federal Circuit that severely limited the protective scope of issued patents and pending patent applications. In the patent application process before the U.S. Patent Office, the specifications and claims in an application may be amended several times to secure an allowance from an examiner. The Federal Circuit in an en banc decision in 2000 held that practically any amendments to a patent application (even as to minor matters of form or secondary language) will automatically constitute a complete bar to alleging equivalency infringement, even against copycats that use elements or methods which are insubstantially different compared to those described in the claims. The Federal Circuit wanted a bright-line test, and absolute certainty in the law.

In the Supreme Court's unanimous decision, the flexible rule and application of the "doctrine of equivalents" was re-established as a cloak which extends patent protection beyond the literal words in claims of a patent, even when those words have been amended during the application process. However, the Court created a rebuttable presumption of surrender, which is an additional burden that a patent owner must bear in any infringement litigation where the patent claim language was amended. Although the prior Festo guillotine was abolished, patent owners still must carry a heavier load. Nonetheless, the Supreme Court's decision recognizes the value of innovation, and the Constitutionally mandated declaration of laws to "Promote the Progress Of Science and the Useful Arts", U.S. Const. Article I, Section 8, Clause 8.

Under the Federal Circuit decision, the day-to-day patent application process would have been drastically revised to avoid the need for amendments in certain cases. As the law now stands, patent attorneys can resume practicing with equivalency in mind, albeit ever more vigilant as to the more stringent legal interpretation, and limitations to the flexible application of the doctrine of equivalents.