Ker–Frisbie rule is a principle that the government's power to try a criminal defendant is not impaired by the defendant’s having been brought back illegally to the United States from a foreign country. The rule is named after the two Supreme Court decisions Ker v. Illinois, 119 U.S. 436, 30 L. Ed. 421, 7 S. Ct. 225 (1886), and Frisbie v. Collins, 342 U.S. 519, 96 L. Ed. 541, 72 S. Ct. 509 (1952), wherein it was held that “the power of a court to try a person for crime is not impaired by the fact that he had been brought within the court's jurisdiction by reason of a forcible abduction.”
Under this rule, due process was limited to the guarantee of a constitutionally fair trial regardless of the method by which jurisdiction was obtained. However, at present Ker-Frisbie rule has eroded, and has had to yield to more recent decisions of the Supreme Court which reflected an expansion of the concept of due process.