Here's the brief amici curiae submitted by five law professors who teach constitutional law, in Horne v. United States Dep't of Agriculture, No. 12-122 (cert. granted. Nov. 20, 2012), supporting the petitioner/property owner. In that case, the Ninth Circuit held the District Court had no jurisdiction to hear a takings defense to the USDA's imposition of a fine, and the only way to raise a takings claim was for the Hornes to institute separate litigation in the Court of Federal Claims for compensation.
Their brief makes two points. First, that Williamson County is "mistaken," and there's nothing standing in the way of the Hornes asserting a takings defense. Second, the Tucker Act does not require the Hornes to raise their takings claims only in the context of a suit for just compensation.
Simply put, Williamson County’s second "ripeness" requirement is a mistake.Williamson County’s constitutional ripeness rule confuses the question of ripeness with the question of remedies. That is, Williamson County took a requirement for when equitable relief is generally available—there must be no adequate remedy at law—and converted it into a constitutional ripeness holding. Properly understood, the availability of an adequate remedy at law is a remedial question, not a jurisdictional one.
Br. at 77. Worth reading.
The petitioners' brief is here. The amicus brief filed by Texas is here. The brief filed by the Cato Institute, the NFIB, the Center for Constitutional Jurisprudence, and the Reason Foundation is here.