Supreme Court of the United States

United States v. Manuel Flores-Montano 

Decided March 30, 2004 – 541 U.S. 149

Chief Justice REHNQUIST delivered the opinion of the [unanimous] Court.

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The Government’s interest in preventing the entry of unwanted persons and effects is at its zenith at the international border. Time and again, we have stated that “searches made at the border, pursuant to the longstanding right of the sovereign to protect itself by stopping and examining persons and property crossing into this country, are reasonable simply by virtue of the fact that they occur at the border.” Congress, since the beginning of our Government, “has granted the Executive plenary authority to conduct routine searches and seizures at the border, without probable cause or a warrant, in order to regulate the collection of duties and to prevent the introduction of contraband into this country.” It is axiomatic that the United States, as sovereign, has the inherent authority to protect, and a paramount interest in protecting, its territorial integrity.

That interest in protecting the borders is illustrated in this case by the evidence that smugglers frequently attempt to penetrate our borders with contraband secreted in their automobiles’ fuel tank. Over the past 5 ½ fiscal years, there have been 18,788 vehicle drug seizures at the southern California ports of entry. Of those 18,788, gas tank drug seizures have accounted for 4,619 of the vehicle drug seizures, or approximately 25%. In addition, instances of persons smuggled in and around gas tank compartments are discovered at the ports of entry of San Ysidro and Otay Mesa at a rate averaging 1 approximately every 10 days. 

Respondent asserts two main arguments with respect to his Fourth Amendment interests. First, he urges that he has a privacy interest in his fuel tank, and that the suspicionless disassembly of his tank is an invasion of his privacy. But on many occasions, we have noted that the expectation of privacy is less at the border than it is in the interior. We have long recognized that automobiles seeking entry into this country may be searched. It is difficult to imagine how the search of a gas tank, which should be solely a repository for fuel, could be more of an invasion of privacy than the search of the automobile’s passenger compartment.

Justice BREYER, concurring.

I join the Court’s opinion in full. I also note that Customs keeps track of the border searches its agents conduct, including the reasons for the searches. This administrative process should help minimize concerns that gas tank searches might be undertaken in an abusive manner.

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In addition to permitting extensive suspicionless searches and seizures at international borders, the Court has permitted similar searches and seizures at checkpoints some distance from the border. The fixed checkpoint at issue in the next case was 66 miles north of the United States-Mexico border.