Article III, Section 1:
The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish. The Judges, both of the supreme and inferior Courts, shall hold their Offices during good Behaviour, and shall, at stated Times, receive for their Services, a Compensation, which shall not be diminished during their Continuance in Office.
Perhaps the fullest expression of the concept of comity may be found in the abstention doctrine. The abstention doctrine instructs federal courts to abstain from exercising jurisdiction if applicable state law, which would be dispositive of the controversy, is unclear and a state court interpretation of the state law question might obviate the necessity of deciding a federal constitutional issue.1 Abstention is not proper, however, where the relevant state law is settled,2 or where it is clear that the state statute or action challenged is unconstitutional no matter how the state court construes state law.3 Federal jurisdiction is not ousted by abstention; rather it is postponed.4 Federal-state tensions would be ameliorated through federal-court deference to the concept that state courts are as adequate a protector of constitutional liberties as the federal courts and through the minimization of the likelihood that state programs would be thwarted by federal intercession. Federal courts would benefit because time and effort would not be expended in decision of difficult constitutional issues which might not require decision.5
During the 1960s, the abstention doctrine was in disfavor with the Supreme Court, suffering rejection in numerous cases, most of them civil rights and civil liberties cases.6 Time-consuming delays7 and piecemeal resolution of important questions8 were cited as a too-costly consequence of the doctrine. Actions brought under the civil rights statutes seem not to have been wholly subject to the doctrine,9 and for awhile cases involving First Amendment expression guarantees seemed to be sheltered as well, but this is no longer the rule.10 Abstention developed robustly with Younger v. Harris,11 and its progeny.