The Declaratory Judgment Act permits a federal district court to grant relief where an actual controversy exists. Whether an actual controversy exists for declaratory judgments of patent non-infringement is governed by the Federal Circuit's test of the "totality of the circumstances." The declaratory judgment plaintiff has the burden of proving an actual controversy exists. However, the declaratory judgment defendant has the burden of proving patent infringement exists. Reasonable apprehension for a suit may be found to exist although the patentee made no patent-based threat. A company fearing business disruption from patent litigation can thus use declaratory judgment actions offensively. Declaratory judgment suits need to be used cautiously and skillfully, with a clear focus on business objectives. Under certain circumstances, a declaratory judgment action of non-infringement is the most prudent and effective way for a company to resolve patent conflicts.
Peter J. Shurn III, Using Declaratory Judgments Offensively in Patent Cases - DJ Jive, 3 J. Marshall Rev. Intell. Prop. L. 1 (2003)