Abstract: Now that same sex marriages have been occurring in Massachusetts for almost a year, the issue of interstate recognition is no longer merely a theoretical issue. Most scholars have either argued that the full faith and credit clause does not mandate recognition of same sex marriages or that it does so for limited purposes or for marriages of Massachusetts residents but not nonresidents seeking to evade their restrictive home state marriage laws. This article argues that the full faith and credit clause should be interpreted to require interstate recognition of same sex marriages validly celebrated in Massachusetts and that Congress does not have the power to deny such recognition under the "effects thereof" language of the full faith and credit clause. Rather than focusing on the rights of same sex couples to have their valid Massachusetts marriages recognized elsewhere, we should focus on the obligations inherent in the marriage relationship. Both Congress and the majority of states have passed so-called Defense of Marriage Acts (DOMAs). If these laws are constitutional, they effectively authorize partners in same sex marriages to relocate to other states and evade their obligations as spouses and parents under Massachusetts law. Those states have made themselves havens for fleeing debtors. Using traditional and modern choice-of-law analysis, as well as analogies to the law of divorce and corporate governance, this article argues that the full faith and credit clause should be interpreted to require recognition of marriages that are valid where celebrated to avoid inconsistent obligations, to allow free interstate travel and commerce, and to prevent the states from authorizing married partners to walk away from their concededly valid and persisting obligations under Massachusetts law.