The European sovereign debt crisis has generated a number of proposals that would have seemed appropriate only for emerging markets just a few years ago, but now are considered as among the few options available to sustain the Eurozone. The leading proposal involves legislation that would mandate collective action clauses in untendered bonds governed under local law. This Note evaluates whether enacting this legislation would generate successful investor claims of invalid expropriation against the sovereign in American courts, and concludes that a successful claim of invalid expropriation is unlikely.