Feasibility is an oft-used concept in political philosophy. But, with very few exceptions, little attention has been devoted to devising a general framework for evaluating claims regarding the feasibility of political prescriptions (e.g., a global carbon tax or a global democratic assembly). I set out to devise such a framework drawing on resources from a familiar account of the semantics of modals (Kratzer 1981, 1991). On my view, feasibility is just a brand of circumstantial possibility- a state of affairs S is feasible just in case the world at which S is realized is accessible from the actual world given the salient limitations on our capacity to realize S. To vindicate this claim, I undertake two tasks. The first is to argue, contrary to much of the extant literature, that feasibility is not a function of nearby notions such as stability, probability of success, or moral costliness. The second is to show- again, contrary to the extant literature- that a modal framework that builds upon the circumstantial accessibility relation yields an appealing approach to evaluating feasibility claims. The upshot is an analysis that not only delivers relatively rigorous feasibility assessments, but also makes clear how feasibility is related to other important constraints on our political theorizing.