Abstract: How does one defend a constitutional theory that's out of the mainstream? Critics of originalism, for example, have described it as a nefarious "Constitution in Exile," a plot to impose abandoned rules on the unsuspecting public. This framing is largely mythical, but it raises a serious objection. If a theory asks us to change our legal practices, leaving important questions to academics or historians, how can it be a theory of our law? If law is a matter of social convention, how can there be conventions that hardly anybody knows about? How is a constitution in exile even possible? This objection is overblown. Legal rules don't always directly reflect common agreement; they can also reflect those agreements indirectly, through conventions that operate at a higher level of abstraction. (We can have social agreement that we're bound by the Internal Revenue Code, even though we don't all agree on -- let alone remember -- everything the Code requires.) So long as we share certain conventions that lead to unconventional conclusions, out-of-the-mainstream theorists can accurately claim to describe our own legal system rather than a foreign or invented one that they hope to impose. The theorists' job is to identify shared premises and to show that they really are shared, even in the face of widespread disagreement at the level of conclusions. In any case, if this kind of objection did have force, it wouldn't be a problem just for out-of-the-mainstream theories like originalism. Virtually no modern legal theory accepts every change in constitutional practice as actually changing the Constitution. Because history moves at its own pace, any theory with meaningful conditions for legal change will often be violated in practice. In other words, any Constitution worth its salt will spend a good bit of time in exile.