opinion: Mr. Justice Stewart
  delivered the opinion of the Court.
  The petitioner in this case, a Mexican citizen holding a valid United States work permit, was convicted of having knowingly received, concealed, and facilitated the transportation of a large quantity of illegally imported marihuana in violation of 21 U. S. C. § 176a (1964 ed.). His sole contention on appeal was that the search of his automobile that uncovered the marihuana was unconstitutional under the Fourth Amendment and that, under the rule of Weeks v. United States, 232 U. S. 383, the marihuana should not have been admitted as evidence against him.
  The basic facts in the case are neither complicated nor disputed. The petitioner was stopped by the United States Border Patrol on State Highway 78 in California, and his car was thoroughly searched. The road is essentially an east-west highway that runs for part of its course through an undeveloped region. At about the point where the petitioner was stopped the road meanders north as well as east — but nowhere does the road reach the Mexican border, and at all points it lies north of U. S. 80, a major east-west highway entirely within the United States that connects the Southwest with the west coast. The petitioner was some 25 air miles north of the border when he was stopped. It is undenied that the Border Patrol had no search warrant, and that there was no probable cause of any kind for the stop or the subsequent search — not even the “reasonable suspicion” found sufficient for a street detention and weapons search in Terry v. Ohio, 392 U. S. 1, and Adams v. Williams, 407 U. S. 143.
  The Border Patrol conducts three types of surveillance along inland roadways, all in the asserted interest of detecting the illegal importation of aliens. Permanent checkpoints are maintained at certain nodal intersections; temporary checkpoints are established from time to time at various places; and finally, there are roving patrols such as the one that stopped and searched the petitioner’s car. In all of these operations, it is argued, the agents are acting within the Constitution when they stop and search automobiles without a warrant, without probable cause to believe the cars contain aliens, and even without probable cause to believe the cars have made a border crossing. The only asserted justification for this extravagant license to search is § 287 (a)(3) of the Immigration and Nationality Act, 66 Stat. 233, 8 U. S. C. §1357 (a) (3), which simply provides for warrantless searches of automobiles and other conveyances “within a reasonable distance from any external boundary of the United States,” as authorized by regulations to be promulgated by the Attorney General. The Attorney General’s regulation, 8 CFR § 287.1, defines “reasonable distance” as “within 100 air miles from any external boundary of the United States.”
  The Court of Appeals for the Ninth Circuit recognized that the search of petitioner’s automobile was not a “border search,” but upheld its validity on the basis of the above-mentioned portion of the Immigration and Nationality Act and the accompanying regulation. 452 F. 2d 459, 461. We granted certiorari, 406 U. S. 944, to consider the constitutionality of the search.
  I
  No claim is made, nor could one be, that the search of the petitioner’s car was constitutional under any previous decision of this Court involving the search of an automobile. It is settled, of course, that a stop and search of a moving automobile can be made without a warrant. That narrow exception to the warrant requirement was first established in Carroll v. United States, 267 U. S. 132. The Court in Carroll approved a portion of the Volstead Act providing for warrantless searches of automobiles when there was probable cause to believe they contained illegal alcoholic beverages. The Court recognized that a moving automobile on the open road presents a situation “where it is not practicable to secure a warrant because the vehicle can be quickly moved out of the locality or jurisdiction in which the warrant must be sought.” Id., at 153. Carroll has been followed in a line of subsequent cases, but the Carroll doctrine does not declare a field day for the police in searching automobiles. Automobile or no automobile, there must be probable cause for the search. As Mr. Justice White wrote for the Court in Chambers v. Maroney, 399 U. S. 42, 51: “In enforcing the Fourth Amendment’s prohibition against unreasonable searches and seizures, the Court has insisted upon probable cause as a minimum requirement for a reasonable search permitted by the Constitution.”
  In seeking a rationale for the validity of the search in this case, the Government thus understandably sidesteps the automobile search cases. Instead, the Government relies heavily on cases dealing with administrative inspections. But these cases fail to support the constitutionality of this search.
  In Camara v. Municipal Court, 387 U. S. 523, the Court held that administrative inspections to enforce community health and welfare regulations could be made on less than probable cause to believe that particular dwellings were the sites of particular violations. Id., at 534-536, 538. Yet the Court insisted that the inspector obtain either consent or a warrant supported by particular physical and demographic characteristics of the areas to be searched. Ibid. See also See v. City of Seattle, 387 U. S. 541. The search in the present case was conducted in the unfettered discretion of the members of the Border Patrol, who did not have a warrant, probable cause, or consent. The search thus embodied precisely the evil the Court saw in Camara when it insisted that the “discretion of the official in the field” be circumscribed by obtaining a warrant prior to the inspection. Camara, supra, at 532-533.
  Two other administrative inspection cases relied upon by the Government are equally inapposite. Colonnade Catering Corp. v. United States, 397 U. S. 72, and United States v. Biswell, 406 U. S. 311, both approved warrantless inspections of commercial enterprises engaged in businesses closely regulated and licensed by the Government. In Colonnade, the Court stressed the long history of federal regulation and taxation of the manufacture and sale of liquor, 397 U. S., at 76-77. In Biswell, the Court noted the pervasive system of regulation and reporting imposed on licensed gun dealers, 406 U. S., at 312 n. 1, 315-316.
  A central difference between those cases and this one is that businessmen engaged in such federally licensed and regulated enterprises accept the burdens as well as the benefits of their trade, whereas the petitioner here was not engaged in any regulated or licensed business. The businessman in a regulated industry in effect consents to the restrictions placed upon him. As the Court stated in Biswell:
  “It is also plain that inspections for compliance with the Gun Control Act pose only limited threats to the dealer’s justifiable expectations of privacy. When a dealer chooses to engage in this pervasively regulated business and to accept a federal license, he does so with the knowledge that his business records, firearms, and ammunition will be subject to effective inspection. Each licensee is annually furnished with a revised compilation of ordinances that describe his obligations and define the inspector’s authority. . . . The dealer is not left to wonder about the purposes of the inspector or the limits of his task.” Id., at 316.
  Moreover, in Colonnade and Biswell, the searching officers knew with certainty that the premises searched were in fact utilized for the sale of liquor or guns. In the present case, by contrast, there was no such assurance that the individual searched was within the proper scope of official scrutiny — that is, there was no reason whatever to believe that he or his automobile had even crossed the border, much less that he was guilty of the commission of an offense.
  II
  Since neither this Court’s automobile search decisions nor its administrative inspection decisions provide any support for the constitutionality of the stop and search in the present case, we are left simply with the statute that purports to authorize automobiles to be stopped and searched, without a warrant and “within a reasonable distance from any external boundary of the United States.” It is clear, of course, that no Act of Congress can authorize a violation of the Constitution. But under familiar principles of constitutional adjudication, our duty is to construe the statute, if possible, in a manner consistent with the Fourth Amendment. Ashwander v. Tennessee Valley Authority, 297 U. S. 288, 348 (Brandéis, J., concurring).
  It is undoubtedly within the power of the Federal Government to exclude aliens from the country. Chae Chan Ping v. United States, 130 U. S. 581, 603-604. It is also without doubt that this power can be effectuated by routine inspections and searches of individuals or conveyances seeking to cross our borders. As the Court stated in Carroll v. United States: “Travellers may be so stopped in crossing an international boundary because of national self protection reasonably requiring one entering the country to identify himself as entitled to come in, and his belongings as effects which may be lawfully brought in.” 267 U. S., at 154. See also Boyd v. United States, 116 U. S. 616.
  Whatever the permissible scope of intrusiveness of a routine border search might be, searches of this kind may in certain circumstances take place not only at the border itself, but at its functional equivalents as well. For example, searches at an established station near the border, at a point marking the confluence of two or more roads that extend from the border, might be functional equivalents of border searches. For another example, a search of the passengers and cargo of an airplane arriving at a St. Louis airport after a nonstop flight from Mexico City would clearly be the functional equivalent of a border search.
  But the search of the petitioner’s automobile by a roving patrol, on a California road that lies at all points at least 20 miles north of the Mexican border, was of a wholly different sort. In the absence of probable cause or consent, that search violated the petitioner’s Fourth Amendment right to be free of “unreasonable searches and seizures.”
  It is not enough to argue, as does the Government, that the problem of deterring unlawful entry by aliens across long expanses of national boundaries is a serious one. The needs of law enforcement stand in constant tension with the Constitution’s protections of the individual against certain exercises of official power. It is precisely the predictability of these pressures that counsels a resolute loyalty to constitutional safeguards. It is well to recall the words of Mr. Justice Jackson, soon after his return from the Nuremberg Trials:
  “These [Fourth Amendment rights], I protest, are not mere second-class rights but belong in the catalog of indispensable freedoms. Among deprivations of rights, none is so effective in cowing a population, crushing the spirit of the individual and putting terror in every heart. Uncontrolled search and seizure is one of the first and most effective weapons in the arsenal of every arbitrary government.” Brinegar v. United States, 338 U. S. 160, 180 (Jackson, J., dissenting).
  The Court that decided Carroll v. United States, supra, sat during a period in our history when the Nation was confronted with a law enforcement problem of no small magnitude — the enforcement of the Prohibition laws. But that Court resisted the pressure of official expedience against the guarantee of the Fourth Amendment. Mr. Chief Justice Taft’s opinion for the Court distinguished between searches at the border and in the interior, and clearly controls the case at bar:
  “It would be intolerable and unreasonable if a prohibition agent were authorized to stop every automobile on the chance of finding liquor and thus subject all persons lawfully using the highways to the inconvenience and indignity of such a search. Travellers may be so stopped in crossing an international boundary because of national self protection reasonably requiring one entering the country to identify himself as entitled to come in, and his belongings as effects which may be lawfully brought in. But those lawfully within the country, entitled to use the public highways, have a right to free passage without interruption or search unless there is known to a competent official authorized to search, probable cause for believing that their vehicles are carrying contraband or illegal merchandise.” 267 U. S., at 153-154.
  Accordingly, the judgment of the Court of Appeals is
  Reversed.
  E. g., Chambers v. Maroney, 399 U. S. 42; Dyke v. Taylor Implement Mfg. Co., 391 U. S. 216; Brinegar v. United States, 338 U. S. 160; Husty v. United States, 282 U. S. 694.
  Moreover, “[n] either Carroll, supra, nor other eases in this Court require or suggest that in every conceivable circumstance the search of an auto even with probable cause may be made without the extra protection for privacy that a warrant affords.” Chambers v. Maroney, supra, at 50. See also Coolidge v. New Hampshire, 403 U. S. 443, 458-464.
  The Justices who join this opinion are divided upon the question of the constitutionality of area search warrants such as described in Mr. Justice Poweli/s concurring opinion.
  With respect to aircraft, 8 CFR §281.1 defines “reasonable distance” as “any distance fixed pursuant to paragraph (b) of this section.” Paragraph (b) authorizes the Commissioner of Immigration and Naturalization to approve searches at a greater distance than 100 air miles from a border “because of unusual circumstances.”
  The Government represents that the highway on which this search occurred is a common route for illegally entered aliens to travel, and that roving patrols apprehended 195 aliens on that road in one year. But it is, of course, quite possible that every one of those aliens was apprehended as a result of a valid search made upon probable cause. On the other hand, there is no telling how many perfectly innocent drivers have been stopped on this road without any probable cause, and been subjected to a search in the trunks, under the hoods, and behind the rear seats of their automobiles.
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