Abstract: When Professor Martin Redish condemned abstention doctrines as violating norms of "institutional legitimacy," he provoked an informative debate, but one that has largely subsided. This Essay revisits the once-heated debate about abstention's legitimacy, clarifies its terms, and identifies its stakes. The legitimacy question is not whether abstention decisions are legally correct, but whether applicable statutes and the Constitution render such decisions ultra vires. Most often, the answer to that question is no. Recent versions of both textualist and purposivist theories of statutory interpretation recognize that statutory meaning always depends on "context." And when relevant statutes are read in a sufficiently capacious semantic context (as textualists would insist) or policy context (as purposivists would demand), abstention emerges as justified in some cases. Indeed, if abstention were illegitimate, then a number of other federal courts doctrines-many of which are difficult to justify by reference either to the language of pertinent statutes or to Congress's most pressing purposes in enacting them-would be illegitimate also.