Licensing of patents is an important route for socially valuable transfers of rights in intellectual property. The continuing value of patent licenses, however, has been called into doubt in view of the Supreme Court's recent Medlmmune, Inc. v. Genentech, Inc. decision. That case held that licensees do not have to repudiate their licenses in order to have Article III standing to seek a declaratory judgment on the validity of licensed patents. MedImmune furthers the federal policy, announced in earlier Supreme Court cases such as Lear, Inc. v. Adkins, of helping licensees police the public domain by eliminating contractual and state-law restrictions on their ability to challenge patent validity. This Article seeks to reconcile the tension between societal interests in getting rid of" bad" patents on the one hand, and in promoting the practice of patent licensing on the other. It argues that licensing parties should contract for, and courts should enforce, clauses that require licensees seeking to challenge patent validity to pursue an inter partes reexamination in the US Patent and Trademark Office. This procedure provides an adequate alternative to district court decla-