necessary in aid of its jurisdiction
Definitions from Case Law · United States Supreme Court
Definitions from Case Law
From 398 U.S. 281 - Atlantic Coast Line Railroad v. Brotherhood of Locomotive Engineers · 1970Most cited · 2,399 citing opinions
While this language is admittedly broad, we conclude that it implies something similar to the concept of injunctions to 'protect or effectuate' judgments. Both exceptions to the general prohibition of § 2283 imply that some federal injunctive relief may be necessary to prevent a state court from so interfering with a federal court's consideration or disposition of a case as to seriously impair the federal court's flexibility and authority to decide that case.
How often courts cite the case defining “necessary in aid of its jurisdiction”
Court decisions citing the opinion that defined “necessary in aid of its jurisdiction” — 2,378 in all, by decade. Counts are citations to the defining case as a whole, not verified uses of the term. The dip in the most recent years is a data-coverage gap, not a real trend — our corpus holds fewer opinions from the latest years.