Am I missing something?

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Congress has now passed, and President Obama has signed, the Lilly Ledbetter Fair Pay Act of 2009, effectively overturning the 2007 Supreme Court opinion in Ledbetter’s case, holding that employees could not sue under Title VII for discrimination that occurred more than 180 days earlier, on a theory that each new paycheck reflects the earlier discrimination. Link

Congress also rejected an amendment that would have made the law prospective only.

Absent from discussions of the new law is whether it is constitutional. The case law is complex – sometimes when a legislature changes a statute of limitations to revive a claim that has lapsed, it is held to violate due process; other times it does not. Personally, I’ve never been able to discern any principled basis for the various distinctions.

Nevertheless, in William Danzer Co. v. Gulf Co., 268 U.S. 633, 636 (1925). In Danzer, the Court held, “On the expiration of the two-year [statute of limitations], it was as if liability had never existed.”

Like the Ledbetter law, Danzer involved a federal statute that created a cause of action, rather than a common law cause of action, and the statute included a statute of limitations. The Court held that Congress could not later revive claims that been extinguished by the limitation period.

Twenty years later, the Court expressed skepticism whether a statute of limitation creates a property right, but did not overrule Danzer, in Chase Securities Corp. v. Donaldson, 325 U.S. 304 (1945).

Congress appears to be aware of possible constitutional problems: the law has a fictional “effective date” of May 28, 2007, the day before the Supreme Court decided the Ledbetter case.

Can anyone explain why the law would not be unconstitutional insofar as it revives claims that have expired?