States have engaged in an intensive process of multilateral treaty making since World War Two despite the fact that few multilateral treaties have fully solved the problems they were designed to address. This inter-disciplinary study of multilateral treaties offers a balanced assessment of the function of multilateral treaties in world politics that draws out the political, as distinct from the legal, meaning of a treaty text. The treaty establishing a regime is regarded as an agreement to set some negotiated limits on pursuit of a common foreign policy goal so that full-blown pursuit of that goal will not bring the States into conflict nor jeopardize any State’s pursuit of that goal. States are then able to continue pursuing that goal with, if anything, renewed vigour, albeit within the agreed limits. Theorising the relationship between a treaty text and its political context establishes a basis on which to critically reconceptualize regime effectiveness and on which to develop ‘treaty strategy’ for use by political actors, including international lawyers.