Ker-Frisbie Doctrine refers to a principle applied in the context of extradition and generally holds that criminal defendants may be prosecuted in U.S. courts regardless of whether their presence has been obtained through the use of applicable extradition treaties. The principle was developed through two cases.
1. Ker v. Illinois, 119 U.S. 436 (U.S. 1886), the U.S. Supreme Court held that "such forcible abduction is no sufficient reason why the party should not answer when brought within the jurisdiction of the court which has the right to try him for such an offence, and presents no valid objection to his trial in such court”.
2. Frisbie v. Collins, 342 U.S. 519 (U.S. 1952), the Supreme Court upheld the conviction over challenges based on due process and federal kidnapping laws.