United States v. Martinez-Fuerte (1976)

Supreme Court of the United States

United States v. Amado Martinez-Fuerte 

Decided July 6, 1976 – 428 U.S. 543


Mr. Justice POWELL delivered the opinion of the Court.

Th[is] case[] involve[s] criminal prosecutions for offenses relating to the transportation of illegal Mexican aliens. [D]efendant was arrested at a permanent checkpoint operated by the Border Patrol away from the international border with Mexico, and [] sought the exclusion of certain evidence on the ground that the operation of the checkpoint was incompatible with the Fourth Amendment. [W]hether the Fourth Amendment was violated turns primarily on whether a vehicle may be stopped at a fixed checkpoint for brief questioning of its occupants even though there is no reason to believe the particular vehicle contains illegal aliens. We hold today that such stops are consistent with the Fourth Amendment. We also hold that the operation of a fixed checkpoint need not be authorized in advance by a judicial warrant.


The respondents are defendants in three separate prosecutions resulting from arrests made on three different occasions at the permanent immigration checkpoint on Interstate 5 near San Clemente, Cal. Interstate 5 is the principal highway between San Diego and Los Angeles, and the San Clemente checkpoint is 66 road miles north of the Mexican border. 

The “point” agent visually screens all northbound vehicles, which the checkpoint brings to a virtual, if not a complete, halt. Most motorists are allowed to resume their progress without any oral inquiry or close visual examination. In a relatively small number of cases the “point” agent will conclude that further inquiry is in order. He directs these cars to a secondary inspection area, where their occupants are asked about their citizenship and immigration status. The Government informs us that at San Clemente the average length of an investigation in the secondary inspection area is three to five minutes. A direction to stop in the secondary inspection area could be based on something suspicious about a particular car passing through the checkpoint, but the Government concedes that none of the three stops at issue was based on any articulable suspicion. During the period when these stops were made, the checkpoint was operating under a magistrate’s “warrant of inspection,” which authorized the Border Patrol to conduct a routine-stop operation at the San Clemente location. 



It is agreed that checkpoint stops are “seizures” within the meaning of the Fourth Amendment. The defendants contend primarily that the routine stopping of vehicles at a checkpoint is invalid because Brignoni-Ponce must be read as proscribing any stops in the absence of reasonable suspicion. [W]e turn first to whether reasonable suspicion is a prerequisite to a valid stop, a question to be resolved by balancing the interests at stake.


Our previous cases have recognized that maintenance of a traffic-checking program in the interior is necessary because the flow of illegal aliens cannot be controlled effectively at the border. We note here only the substantiality of the public interest in the practice of routine stops for inquiry at permanent checkpoints, a practice which the Government identifies as the most important of the traffic-checking operations. These checkpoints are located on important highways; in their absence such highways would offer illegal aliens a quick and safe route into the interior. Routine checkpoint inquiries apprehend many smugglers and illegal aliens who succumb to the lure of such highways. And the prospect of such inquiries forces others onto less efficient roads that are less heavily traveled, slowing their movement and making them more vulnerable to detection by roving patrols.

A requirement that stops on major routes inland always be based on reasonable suspicion would be impractical because the flow of traffic tends to be too heavy to allow the particularized study of a given car that would enable it to be identified as a possible carrier of illegal aliens. In particular, such a requirement would largely eliminate any deterrent to the conduct of well-disguised smuggling operations, even though smugglers are known to use these highways regularly.


While the need to make routine checkpoint stops is great, the consequent intrusion on Fourth Amendment interests is quite limited. The stop does intrude to a limited extent on motorists’ right to “free passage without interruption,” and arguably on their right to personal security. But it involves only a brief detention of travelers during which “‘[a]ll that is required of the vehicle’s occupants is a response to a brief question or two and possibly the production of a document evidencing a right to be in the United States.’” 

Neither the vehicle nor its occupants are searched, and visual inspection of the vehicle is limited to what can be seen without a search. This objective intrusion the stop itself, the questioning, and the visual inspection also existed in roving-patrol stops. But we view checkpoint stops in a different light because the subjective intrusion—the generating of concern or even fright on the part of lawful travelers—is appreciably less in the case of a checkpoint stop. 


Routine checkpoint stops do not intrude similarly on the motoring public. First, the potential interference with legitimate traffic is minimal. Motorists using these highways are not taken by surprise as they know, or may obtain knowledge of, the location of the checkpoints and will not be stopped elsewhere. Second, checkpoint operations both appear to and actually involve less discretionary enforcement activity. The regularized manner in which established checkpoints are operated is visible evidence, reassuring to law-abiding motorists, that the stops are duly authorized and believed to serve the public interest. The location of a fixed checkpoint is not chosen by officers in the field, but by officials responsible for making overall decisions as to the most effective allocation of limited enforcement resources. We may assume that such officials will be unlikely to locate a checkpoint where it bears arbitrarily or oppressively on motorists as a class. And since field officers may stop only those cars passing the checkpoint, there is less room for abusive or harassing stops of individuals than there was in the case of roving-patrol stops. Moreover, a claim that a particular exercise of discretion in locating or operating a checkpoint is unreasonable is subject to post-stop judicial review. 



In summary, we hold that stops for brief questioning routinely conducted at permanent checkpoints are consistent with the Fourth Amendment and need not be authorized by warrant. The principal protection of Fourth Amendment rights at checkpoints lies in appropriate limitations on the scope of the stop. We have held that checkpoint searches are constitutional only if justified by consent or probable cause to search. And our holding today is limited to the type of stops described in this opinion. “[A]ny further detention … must be based on consent or probable cause.” None of the defendants in these cases argues that the stopping officers exceeded these limitations. We reverse the judgment of the Court of Appeals for the Ninth Circuit and remand the case with directions to affirm the conviction of Martinez-Fuerte.

Mr. Justice BRENNAN, with whom Mr. Justice MARSHALL joins, dissenting.

Today’s decision is the ninth this Term marking the continuing evisceration of Fourth Amendment protections against unreasonable searches and seizures. Consistent with this purpose to debilitate Fourth Amendment protections, the Court’s decision today virtually empties the Amendment of its reasonableness requirement by holding that law enforcement officials manning fixed checkpoint stations who make standardless seizures of persons do not violate the Amendment. I dissent.

We are told today [] that motorists without number may be individually stopped, questioned, visually inspected, and then further detained without even a showing of articulable suspicion, let alone the heretofore constitutional minimum of reasonable suspicion, a result that permits search and seizure to rest upon “nothing more substantial than inarticulate hunches.” This defacement of Fourth Amendment protections is arrived at by a balancing process that overwhelms the individual’s protection against unwarranted official intrusion by a governmental interest said to justify the search and seizure. But that method is only a convenient cover for condoning arbitrary official conduct. 


Since the objective is almost entirely the Mexican illegally in the country, checkpoint officials, uninhibited by any objective standards and therefore free to stop any or all motorists without explanation or excuse, wholly on whim, will perforce target motorists of Mexican appearance. The process will then inescapably discriminate against citizens of Mexican ancestry and Mexican aliens lawfully in this country for no other reason than that they unavoidably possess the same “suspicious” physical and grooming characteristics of illegal Mexican aliens.

Every American citizen of Mexican ancestry and every Mexican alien lawfully in this country must know after today’s decision that he travels the fixed checkpoint highways at the risk of being subjected not only to a stop, but also to detention and interrogation, both prolonged and to an extent far more than for non-Mexican appearing motorists. To be singled out for referral and to be detained and interrogated must be upsetting to any motorist. One wonders what actual experience supports my Brethren’s conclusion that referrals “should not be frightening or offensive because of their public and relatively routine nature.” In point of fact, referrals viewed in context, are not relatively routine; thousands are otherwise permitted to pass. But for the arbitrarily selected motorists who must suffer the delay and humiliation of detention and interrogation, the experience can obviously be upsetting. And that experience is particularly vexing for the motorist of Mexican ancestry who is selectively referred, knowing that the officers’ target is the Mexican alien. That deep resentment will be stirred by a sense of unfair discrimination is not difficult to foresee.49

In short, if a balancing process is required, the balance should be struck to require that Border Patrol officers act upon at least reasonable suspicion in making checkpoint stops. In any event, even if a different balance were struck, the Court cannot, without ignoring the Fourth Amendment requirement of reasonableness, justify wholly unguided seizures by officials manning the checkpoints. 

The cornerstone of this society, indeed of any free society, is orderly procedure. The Constitution, as originally adopted, was therefore, in great measure, a procedural document. For the same reasons the drafters of the Bill of Rights largely placed their faith in procedural limitations on government action. The Fourth Amendment’s requirement that searches and seizures be reasonable enforces this fundamental understanding in erecting its buffer against the arbitrary treatment of citizens by government. But to permit, as the Court does today, police discretion to supplant the objectivity of reason and, thereby, expediency to reign in the place of order, is to undermine Fourth Amendment safeguards and threaten erosion of the cornerstone of our system of a government, for, as Mr. Justice Frankfurter reminded us, “[t]he history of American freedom is, in no small measure, the history of procedure.” 

Notes, Comments, and Questions 

A police officer is 66 miles from the Canadian border. There is no checkpoint. The officer spots a car and is suspicious that it contains Canadians who are not legally in the United States. How much evidence must the officer have to stop the car to conduct a brief investigation of its occupants?

What is your authority for your answer to the previous question? If you do not have authority to which you can refer, review the Court’s opinion in Martinez-Fuerte. In that opinion, which mostly concerned fixed checkpoints, the Court referred to prior law concerning roving patrols.

Notes, Comments, and Questions 

Students should be aware of three ongoing controversies related to border enforcement: (1) the existence and significance of an “extended border” and areas known as the “functional equivalent” of the border, (2) the treatment of electronic devices crossing the border, and (3) the treatment of persons crossing the border seeking asylum or otherwise fleeing persecution and poverty.

The Functional Border and Extended Border

International airports and the land immediately surrounding those airports are treated as the “functional equivalent” of the border. Accordingly, a traveler flying from England to St. Louis could be subjected to the same searches permissible at the border itself.

More controversially, federal officials have argued that they possess search and seizure authority within 100 miles of international borders in an area known as the “extended border.” See, e.g., 8 C.F.R. § 287.1. If all authority granted to law enforcement at the physical border exists throughout the extended border, then people in New York City, Los Angeles, Houston, New Orleans, Seattle, Washington, D.C., and all of Florida could be subjected to suspicionless searches of their persons and effects at will. Civil libertarian organizations have accordingly decried the concept of the extended border, calling it an unlawful “Constitution-Free Zone.”

The map below illustrates the ACLU’s take on the extended border: 

"The Constitution-Free Zone of the United States" map drawn by the ACLU indicates with orange color the area of the country within 100 miles of the border.

It is not clear precisely what authority federal officials claim to possess in the extended border—official guidance documents differ, and actual practice can diverge from such documents—nor is there robust judicial guidance. In an era of increasingly-vigorous immigration enforcement, this issue is attracting more attention. 


Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Criminal Procedure: Undergraduate Edition Copyright © 2022 by Christopher E. Smith is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

Share This Book