Which case is cited as the business purpose doctrine: Gregory v. Helvering or Ableman v. Booth?
Ableman v. Booth Ableman v. Booth, 62 U.S. 506 (1859) , was a United States Supreme Court case in which the Court held that State courts cannot issue rulings on federal law that contradict the decisions of federal courts, overturning a decision by the Supreme Court of Wisconsin. The Supreme Court held that under the Constitution, the federal courts have the final power to decide cases arising under the Constitution and federal statutes, and that the States do not have the power to overturn those decisions. Thus, Wisconsin did not have the authority to nullify federal judgments or statutes.
Exigent circumstance An exigent circumstance, in the criminal procedure law of the United States, allows law enforcement, under certain circumstances, to enter a structure without a search warrant or, if they have a "knock and announce" warrant, without knocking and waiting for refusal. It must be a situation where people are in imminent danger, evidence faces imminent destruction, or a suspect's imminent escape. Once entry is obtained, the plain view doctrine applies, allowing the seizure of any evidence or contraband discovered in the course of actions consequent upon the exigent circumstances.