What is the test for admitting evidence seized as a result of an illegal warrantless search of the person and his vehicle?

Mack argues that the district court improperly admitted evidence seized as the result of an illegal warrantless search of his person and his vehicle. Mack agrees with the district court that he was arrested at the time that he was ordered out of his van, but he disagrees that the police had probable cause to make the arrest. In support, Mack cites Henry v. United States, 361 U.S. 98 (1959), which states that the Fourth Amendment requires that officers must have probable cause in order to make a warrantless arrest. Id. at 100. Mack argues that the officers lacked sufficient evidence from which to form probable cause. ¹