The Fourth Amendment requires persons arrested without a warrant to be promptly brought before a neutral magistrate for a judicial determination of probable cause. There is no mandated time frame for the prompt judicial determination. Promptness merely requires the judicial determination to be made without unreasonable delay. A judicial determination made within 48 hours after the arrest is presumably prompt, unless the person under arrest demonstrates unreasonable delay. If the determination is not made within 48 hours, the government bears the burden to demonstrate extraordinary circumstances to justify the delay.