The major abstention doctrines are:
- Younger abstention ("Federal courts may enjoin pending state administrative proceedings that vindicate important state interests only in extraordinary circumstances.")
- Pullman abstention (when a constitutional issue might be avoided by allowing state courts to interpret an ambiguous state law)
- Colorado River abstention doctrine (avoid duplicative proceedings in another state or federal court)
These circumstances include the following:
- Federal courts have the power to refrain from hearing cases that would interfere with a pending state criminal proceeding, see Younger v. Harris, 401 U.S. 37 (1971), or with certain types of state civil proceedings, see Huffman v. Pursue, Ltd., 420 U.S. 592 (1975); Juidice v. Vail, 430 U.S. 327 (1977); cases in which the resolution of a federal constitutional question might be obviated if the state courts were given the opportunity to interpret ambiguous state law, see Railroad Comm'n of Tex. v. Pullman Co., 312 U.S. 496 (1941); cases raising issues "intimately involved with [the States'] sovereign prerogative," the proper adjudication of which might be impaired by unsettled questions of state law, see Louisiana Power & Light Co. v. City of Thibodaux, 360 U.S. 25, 28 (1959); id., at 31 (Stewart, J., concurring); cases whose resolution by a federal court might unnecessarily interfere with a state system for the collection of taxes, see Great Lakes Dredge & Dock Co. v. Huffman, 319 U.S. 293 (1943); and cases which are duplicative of a pending state proceeding, see Colorado River Water Conservation Dist. v. United States, 424 U.S. 800 (1976); Pennsylvania v. Williams, 294 U.S. 176 (1935).
|“||the extraordinary decision to stay federal adjudication requires more than an ambiguity in state law and a likelihood of avoiding constitutional adjudication. A district court must carefully assess the totality of circumstances presented by a particular case. This requires a broad inquiry which should include consideration of the rights at stake and the costs of delay pending state court adjudication.||”|