Federalism.When one state, such as Massachusetts, adopts gay marriage, the Full Faith and Credit Clause of the Constitution might reasonably be applied to require other states to recognize such marriages, and thus essentially force it upon the rest of the nation. Federalism, however, is meant to allow states the autonomy of social experimentation (as with Oregon's legalization of assisted suicide) from which other states can learn. It is not intended to force other states to follow.