Mr. Justice Clark
delivered the opinion of the Court.
This case concerns an alien immigrant permanently excluded from the United States on security grounds but stranded in his temporary haven on Ellis Island because other countries will not take him back. The issue is whether the Attorney General’s continued exclusion of respondent without a hearing amounts to an unlawful detention, so that courts may admit him temporarily to the United States on bond until arrangements are made for his departure abroad. After a hearing on respondent’s petition for a writ of habeas corpus, the District Court so held and authorized his temporary admission on $5,000 bond. The Court of Appeals affirmed that action, but directed reconsideration of the terms of the parole. Accordingly, the District Court entered a modified order reducing bond to $3,000 and permitting respondent to travel and reside in Buffalo, New York. Bond was posted and respondent released. Because of resultant serious problems in the enforcement of the immigration laws, we granted certiorari. 344 U. S. 809.
Respondent’s present dilemma springs from these circumstances: Though, as the District Court observed, “[t]here is a certain vagueness about [his] history,” respondent seemingly was born in Gibraltar of Hungarian or Rumanian parents and lived in the United States from 1923 to 1948. In May of that year he sailed for Europe, apparently to visit his dying mother in Rumania. Denied entry there, he remained in Hungary for some 19 months, due to “difficulty in securing an exit permit.” Finally, armed with a quota immigration visa issued by the American Consul in Budapest, he proceeded to France and boarded the lie de France in Le Havre bound for New York. Upon arrival on February 9, 1950, he was temporarily excluded from the United States by an immigration inspector acting pursuant to the Passport Act as amended and regulations thereunder. Pending disposition of his case he was received at Ellis Island. After reviewing the evidence, the Attorney General on May 10, 1950, ordered the temporary exclusion to be made permanent without a hearing before a board of special inquiry, on the “basis of information of a confidential nature, the disclosure of which would be prejudicial to the public interest.” That determination rested on a finding that respondent’s entry would be prejudicial to the public interest for security reasons. But thus far all attempts to effect respondent’s departure have failed: Twice he shipped out to return whence he came; France and Great Britain refused him permission to land. The State Department has unsuccessfully negotiated with Hungary for his readmission. Respondent personally applied for entry to about a dozen Latin-American countries but all turned him down. So in June 1951 respondent advised the Immigration and Naturalization Service that he would exert no further efforts to depart. In short, respondent sat on Ellis Island because this country shut him out and others were unwilling to take him in.
Asserting unlawful confinement on Ellis Island, he sought relief through a series of habeas corpus proceedings. After four unsuccessful efforts on respondent’s part, the United States District Court for the Southern District of New York on November 9, 1951, sustained the writ. The District Judge, vexed by the problem of “an alien who has no place to go,” did not question the validity of the exclusion order but deemed further “detention” after 21 months excessive and justifiable only by affirmative proof of respondent’s danger to the public safety. When the Government declined to divulge such evidence, even in camera, the District Court directed respondent’s conditional parole on bond. By a divided vote, the Court of Appeals affirmed. Postulating that the power to hold could never be broader than the power to remove or shut out and that to “continue an alien’s confinement beyond that moment when deportation becomes patently impossible is to deprive him of his liberty,” the court found respondent’s “confinement” no longer justifiable as a means of removal elsewhere, thus not authorized by statute, and in violation of due process. Judge Learned Hand, dissenting, took a different view: The Attorney General’s order was one of “exclusion” and not “deportation”; respondent’s transfer from ship to shore on Ellis Island conferred no additional rights; in fact, no alien so situated “can force us to admit him at all.”
Courts have long recognized the power to expel or exclude aliens as a fundamental sovereign attribute exercised by the Government’s political departments largely immune from judicial control. The Chinese Exclusion Case, 130 U. S. 581 (1889); Fong Yue Ting v. United States, 149 U. S. 698 (1893); Knauff v. Shaughnessy, 338 U. S. 537 (1950); Harisiades v. Shaughnessy, 342 U. S. 580 (1952). In the exercise of these powers, Congress expressly authorized the President to impose additional restrictions on aliens entering or leaving the United States during periods of international tension and strife. That authorization, originally enacted in the Passport Act of 1918, continues in effect during the present emergency. Under it, the Attorney General, acting for the President, may shut out aliens whose “entry would be prejudicial to the interests of the United States.” And he may exclude without a hearing when the exclusion is based on confidential information the disclosure of which may be prejudicial to the public interest. The Attorney General in this case proceeded in accord with these provisions; he made the necessary determinations. and barred the alien from entering the United States.
It is true that aliens who have once passed through our gates, even illegally, may be expelled only after proceedings conforming to traditional standards of fairness encompassed in due process of law. The Japanese Immigrant Case, 189 U. S. 86, 100-101 (1903); Wong Yang Sung v. McGrath, 339 U. S. 33, 49-50 (1950); Kwong Hai Chew v. Colding, 344 U. S. 590, 598 (1953). But an alien on the threshold of initial entry stands on a different footing: “Whatever the procedure authorized by Congress is, it is due process as far as an alien denied entry is concerned.” Knauff v. Shaughnessy, supra, at 544; Ekiu v. United States, 142 U. S. 651, 660 (1892). And because the action of the executive officer under such authority is final and conclusive, the Attorney General cannot be compelled to disclose the evidence underlying his determinations in an exclusion case; “it is not within the province of any court, unless expressly authorized by law, to review the determination of the political branch of the Government.” Knauff v. Shaughnessy, supra, at 543; Ekiu v. United States, supra, at 660. In a case such as this, courts cannot retry the determination of the Attorney General. Knauff v. Shaughnessy, supra, at 546; Ludecke v. Watkins, 335 U. S. 160, 171-172 (1948).
Neither respondent’s harborage on Ellis Island nor his prior residence here transforms this into something other than an exclusion proceeding. Concededly, his movements are restrained by authority of the United States, and he may by habeas corpus test the validity of his exclusion. But that is true whether he enjoys temporary refuge on land, Ekiu v. United States, supra, or remains continuously aboard ship. United States v. Jung Ah Lung, 124 U. S. 621, 626 (1888); Chin Yow v. United States, 208 U. S. 8, 12 (1908). In sum, harborage at Ellis Island is not an entry into the United States. Kaplan v. Tod, 267 U. S. 228, 230 (1925); United States v. Ju Toy, 198 U. S. 253, 263 (1905); Ekiu v. United States, supra, at 661. For purposes of the immigration laws, moreover, the legal incidents of an alien’s entry remain unaltered whether he has been here once before or not. He is an entering alien just the same, and may be excluded if unqualified for admission under existing immigration laws. E. g., Lem Moon Sing v. United States, 158 U. S. 538, 547-548 (1895); Polymeris v. Trudell, 284 U. S. 279 (1932).
To be sure, a lawful resident alien may not captiously be deprived of his constitutional rights to procedural due process. Kwong Hai Chew v. Colding, 344 U. S. 590, 601 (1953); cf. Delgadillo v. Carmichael, 332 U. S. 388 (1947). Only the other day we held that under some circumstances temporary absence from our shores cannot constitutionally deprive a returning lawfully resident alien of his right to be heard. Kwong Hai Chew v. Colding, supra. Chew, an alien seaman admitted by an Act of Congress to permanent residence in the United States, signed articles of maritime employment as chief steward on a vessel of American registry with home port in New York City. Though cleared by the Coast Guard for his voyage, on his return from four months at sea he was “excluded” without a hearing on security grounds. On the facts of that case, including reference to § 307 (d) (2) of the Nationality Act of 1940, we felt justified in “assimilating” his status for constitutional purposes to that of continuously present alien residents entitled to hearings at least before an executive or administrative tribunal. Id., at 596, 599-601. Accordingly, to escape constitutional conflict we held the administrative regulations authorizing exclusion without hearing in certain security cases inapplicable to aliens so protected by the Fifth Amendment. Id., at 600.
But respondent’s history here drastically differs from that disclosed in Chew’s case. Unlike Chew who with full security clearance and documentation pursued his vocation for four months aboard an American ship, respondent, apparently without authorization or reentry papers, simply left the United States and remained behind the Iron Curtain for 19 months. Moreover, while § 307 of the 1940 Nationality Act regards maritime service such as Chew’s to be continuous residence for naturalization purposes, that section deems protracted absence such as respondent’s a clear break in an alien’s continuous residence here. In such circumstances, we have no difficulty in holding respondent an entrant alien or “assimilated to [that] status” for constitutional purposes. Id., at 599. That being so, the Attorney General may lawfully exclude respondent without a hearing as authorized by the emergency regulations promulgated pursuant to the Passport Act. Nor need he disclose the evidence upon which that determination rests. Knauff v. Shaughnessy, 338 U. S. 537 (1950).
There remains the issue of respondent’s continued exclusion on Ellis Island. Aliens seeking entry from contiguous lands obviously can be turned back at the border without more. Polymeris v. Trudell, 284 U. S. 279 (1932). While the Government might keep entrants by sea aboard the vessel pending determination of their admissibility, resulting hardships to the alien and inconvenience to the carrier persuaded Congress to adopt a more generous course. By statute it authorized, in cases such as this, aliens’ temporary removal from ship to shore. But such temporary harborage, an act of legislative grace, bestows no additional rights. Congress meticulously specified that such shelter ashore “shall not be considered a landing” nor relieve the vessel of the duty to transport back the alien if ultimately excluded. And this Court has long considered such temporary arrangements as not affecting an alien’s status; he is treated as if stopped at the border. Ekiu v. United States, 142 U. S. 651, 661-662 (1892); United States v. Ju Toy, 198 U. S. 253, 263 (1905); Kaplan v. Tod, 267 U. S. 228, 230 (1925).
Thus we do not think that respondent’s continued exclusion deprives him of any statutory or constitutional right. It is true that resident aliens temporarily detained pending expeditious consummation of deportation proceedings may be released on bond by the Attorney General whose discretion is subject to judicial review. Carlson v. Landon, 342 U. S. 524 (1952). By that procedure aliens uprooted from our midst may rejoin the community until the Government effects their leave. An exclusion proceeding grounded on danger to the national security, however, presents different considerations; neither the rationale nor the statutory authority for such release exists. Ordinarily to admit an alien barred from entry on security grounds nullifies the very purpose of the exclusion proceeding; Congress in 1950 declined to include such authority in the statute. That exclusion by the United States plus other nations’ inhospitality results in present hardship cannot be ignored. But, the times being what they are, Congress may well have felt that other countries ought not shift the onus to us; that an alien in respondent’s position is no more ours than theirs. Whatever our individual estimate of that policy and the fears on which it rests, respondent’s right to enter the United States depends on the congressional will, and courts cannot substitute their judgment for the legislative mandate. Harisiades v. Shaughnessy, 342 U. S. 580, 590-591 (1952).
Reversed.
101 F. Supp. 66 (1951).
195 F. 2d 964 (C. A. 2d Cir. 1952).
101 F. Supp., at 67.
101 F. Supp., at 67, 70; R. 26-27.
195 F. 2d, at 967, 968.
Id., at 970.
Section 1 of the Act of May 22, 1918, c. 81, 40 Stat. 559, as amended by the Act of June 21, 1941, c. 210, § 1, 55 Stat. 252, 22 U. S. C. § 223, provides in pertinent part:
“When the United States is at war or during the existence of the national emergency proclaimed by the President on May 27, 1941, or as to aliens whenever there exists a state of war between, or among, two or more states, and the President shall find that the interests of the United States require that restrictions and prohibitions in addition to those provided otherwise than by this Act be imposed upon the departure of persons from and their entry into the United States, and shall make public proclamation thereof, it shall, until otherwise ordered by the President or Congress, be unlawful—
“(a) For any alien to depart from or enter or attempt to depart from or enter the United States except under such reasonable rules, regulations, and orders, and subject to such limitations and exceptions as the President shall prescribe; . . .
That authorization has been extended to cover the dates relevant in this case. 66 Stat. 54, 96, 137, 330. Pursuant to that authority,
Presidential Proclamation No. 2523, 6 Fed. Reg. 5821, as promulgated in 1941 in part provided:
“No alien shall be permitted to enter the United States if it appears to the satisfaction of the Secretary of State that such entry would be prejudicial to the interests of the United States as provided in the rules and regulations hereinbefore authorized to be prescribed by the Secretary of State, with the concurrence of the Attorney General.” The Secretary of State, with the concurrence of the Attorney General, issued applicable regulations codified as Part 175 of 8 CFR. Section 175.53 defines eleven categories of aliens whose entry is “deemed to be prejudicial to the interests of the United States.” That delegation of authority has been upheld. Knauff v. Shaughnessy, 338 U. S. 537 (1950). The regulations were ratified and confirmed by Presidential Proclamation No. 2850, 14 Fed. Reg. 5173, promulgated August 17, 1949.
8 CFR § 175.57 provides:
“§ 175.57 Entry not permitted in special cases, (a) Any alien, even though in possession of a permit to enter, or exempted under §§175.41 to 175.62, inclusive, from obtaining a permit to enter, may be excluded temporarily if at the time he applies for admission at a port of entry it appears that he is or may be excludable under one of the categories set forth in § 175.53. The official excluding the alien shall immediately report the facts to the head of his department, who will communicate such report to the Secretary of State. Any alien so temporarily excluded by an official of the Department of Justice shall not be admitted and shall be excluded and deported unless the Attorney General, after consultation with the Secretary of State, is satisfied that the admission of the alien would not be prejudicial to the interests of the United States. Any alien so temporarily excluded by any other official shall not be admitted and shall be excluded and deported unless the Secretary of State is satisfied that the admission of the alien would not be prejudicial to the interests of the United States.
“(b) In the case of an alien temporarily excluded by an official of the Department of Justice on the ground that he is, or may be excludable under one or more of the categories set forth in § 175.53, no hearing by a board of special inquiry shall be held until after the casé is reported to the Attorney General and such a hearing is directed by the Attorney General or his representative. In any special case the alien may be denied a hearing before a board of special inquiry and an appeal from the decision of that board if the Attorney General determines that he is excludable under one of the categories set forth in § 175.53 on the basis of information of a confidential nature, the disclosure of which would be prejudicial to the public interest.”
See 8 U. S. C. § 210. Of course, neither a reentry permit, issuable upon proof of prior lawful admission to the United States, § 210 (b), nor an immigration visa entitles an otherwise inadmissible alien to entry. §§210 (f), 202 (g). An immigrant is not unaware of this; § 202 (g) directs those facts to be “printed conspicuously upon every immigration visa.” For a recent study of entry procedures with recommendations, see Report of the President’s Commission on Immigration and Naturalization (1953), cc. 10-11.
8 U. S. C. § 707; United States v. Larsen, 165 F. 2d 433 (C. A. 2d Cir. 1947).
8 U. S. C. § 151.
8 U. S. C. §§ 151, 154.
8 U. S. C. (Supp. V) § 156. We there noted that “the problem of habeas corpus after unusual delay in deportation hearings is not involved in this case.” 342 U. S., at 546. (Emphasis added.)
8 U. S. C. § 154 permits temporary suspension of deportation of excluded aliens whose testimony is needed on behalf of the United States. Manifestly respondent does not fall within that class. While the essence of that provision is retained in § 237 (d) of the Immigration and Nationality Act of 1952, 66 Stat. 202, § 212 (d) (5) of that Act, 66 Stat. 188, vests new and broader discretion in the Attorney General. Cf. 8 U. S. C. §§ 136 (p) (q); 8 U. S. C. (Supp. V) § 137-5 (a) (b). Those provisions are not now here.
See S. Rep. No. 1515, 81st Cong., 2d Sess. 643-644.