In Gerstein v. Pugh et al., the U.S. Supreme Court ruled that a person arrested without a warrant must promptly receive a judicial determination of probable cause, as required by the Fourth Amendment. The case involved two Florida inmates who had been detained for substantial periods of time after their arrest but before any formal charge or trial took place. They argued that this violated their constitutional rights to due process and protection against unreasonable seizures. The court agreed, stating that while police may detain an individual briefly following an unwarranted arrest in order to investigate further, prolonged detention requires either consent from the detainee or approval from a neutral magistrate based on evidence supporting probable cause.

In the dissenting opinion for Gerstein v. Pugh, Justice Powell argued that the majority's decision to require a judicial determination of probable cause after an arrest but before detention or trial was unnecessary and impractical. He believed this requirement would place an undue burden on already overworked lower courts without significantly improving protections for defendants' rights. Furthermore, he contended that existing procedures were sufficient in preventing unlawful detentions as they provided opportunities for arrested individuals to challenge their arrests through habeas corpus petitions or motions to suppress evidence obtained from illegal arrests. Additionally, Justice Powell expressed concern about potential delays in criminal proceedings due to the need for additional hearings and questioned whether these delays might infringe upon defendants' right to a speedy trial.