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.
In Cohens v. Virginia, Chief Justice John Marshall proclaimed that for a court not to exercise the jurisdiction that Congress had conferred on it would constitute "treason to the constitution."1 In the even more iconic case of Marbury v. Madison, the Supreme Court rested the necessity of judicial review at least partly on the mandatory character of its jurisdiction.2 In noting that it must rule on constitutional issues to decide cases in which such issues arose,3 the Court did not even consider that it might, alternatively, respond to cases presenting constitutional issues by declining to exercise jurisdiction at all. Subsequent decisions have echoed similar themes about federal courts' absolute, or at least nearly invariant, obligation to exercise the jurisdiction that Congress confers on them.4
As is also well known, however, federal courts law includes a number of judge-made abstention doctrines under which federal courts do precisely what Cohens said they must not: although acknowledging jurisdiction over a case, they decline to exercise it. Perhaps the two best known abstention doctrines are Pullman and Younger abstention.5 Under Pullman, federal courts will initially decline to exercise jurisdiction over cases in which plaintiffs present sensitive federal constitutional claims that the resolution of a difficult state law issue might moot or alter.6 Instead, federal courts will wait for state courts to resolve the state law issues that might make the resolution of federal constitutional claims unnecessary. The Younger doctrine takes its name from Younger v. Harris, in which the Supreme Court held that federal courts must virtually always abstain from adjudicating suits seeking injunctions against pending state criminal proceedings.7 Subsequent cases have extended Younger abstention to encompass suits for injunctions against a broader array of state judicial and quasi-judicial proceedings,8 including some in which neither a state nor its officials appeared as parties.9 At Younger's high tide during the 1970s and early 1980s, the Court flirted with extending its bar from suits to enjoin judicial proceedings to suits challenging the law enforcement practices of state executive officials.10
The most fundamental question about federal abstention doctrines involves what I shall characterize as their legal legitimacy. "Legitimacy" is an elusive term, which can mean different things in different contexts.11 In the aspect with which I am concerned, it speaks to issues of lawful authority rather than to questions about whether authority is exercised correctly, wisely, or well.12 In the case of abstention doctrines, the legitimacy question is whether a court that decides to abstain from deciding a case within its jurisdiction acts ultra vires, by making a kind of decision that the Constitution and applicable statutes manifestly give it no authority to make. …