A more thorough explanation:

The Ker-Frisbie Rule is a legal principle that states that the government's power to try a criminal defendant is not affected by the defendant's illegal return to the United States from a foreign country.

For example, if a person commits a crime in the United States and then flees to another country, the government may use legal means to bring that person back to the United States to stand trial. Even if the person was brought back illegally, the government can still try them for the crime they committed.

This principle was established in two court cases: Ker v. Illinois in 1886 and Frisbie v. Collins in 1952. In both cases, the defendants argued that their trials were invalid because they had been brought back to the United States illegally. However, the courts ruled that the government's power to try them was not affected by the manner in which they were brought back.