United States v. Flores-Montano

Facts of the Case

Customs officials seized 37 kilograms of marijuana from defendant’s gas tank at the international border. Defendant was indicted of unlawfully importing marijuana and of possession of marijuana with intent to distribute. Defendant moved to suppress the marijuana. The district court granted the motion, which the appellate court affirmed. The United States Supreme Court granted certiorari to petitioner United States.


Does the Fourth Amendment require customs officers at the international border to have reasonable suspicion in order to remove, disassemble, and search a vehicle’s gas tank for illegal material?


No. In a unanimous opinion delivered by Chief Justice William Rehnquist, the Court held that the government had authority to inspect a vehicle’s fuel tank at the border without suspicion. Though the Fourth Amendment ‘protects property as well as privacy,’ interference with a vehicle owner’s gas tank is justified by the Government’s paramount interest in protecting the border. The Court rejected the argument that the requirement of suspicion for highly intrusive searches of people be carried over to cars (especially at the border): Complex balancing tests…have no place in border searches of vehicles.

Case Information

  • Citation: 541 US 149 (2004)
  • Granted: Oct 14, 2003
  • Argued: Feb 25, 2004
  • Decided Mar 30, 2004