opinion: IMMIGRATION AND NATURALIZATION SERVICE v. MIRANDA
  No. 82-29.
  Decided November 8, 1982
  Per Curiam.
  Respondent Horacio Miranda, a citizen of the Philippines, entered the United States in. 1971 on a temporary visitor’s visa. After his visa expired, he stayed in this country, eventually marrying Linda Milligan, a citizen of the United States, on May 26, 1976. Shortly thereafter, Milligan filed a visa petition with the Immigration and Naturalization Service (INS) on respondent’s behalf. She requested that he be granted an immigrant visa as her spouse. Respondent simultaneously filed an application requesting the INS to adjust his status to that of a permanent resident alien. Section 245(a) of the Immigration and Nationality Act of 1952 conditions the granting of permanent resident status to an alien on the immediate availability of an immigrant visa. Milligan’s petition, if approved, would have satisfied this condition.
  The INS did not act on either Milligan’s petition or respondent’s application for 18 months. Following the breakup of her marriage with respondent, Milligan withdrew her petition in December 1977. At that point, the INS denied respondent’s application for permanent residence because he had not shown that an immigrant visa was immediately available to him. The INS also issued an order to show cause why he should not be deported.
  At a deportation hearing, respondent conceded his depor-tability but renewed his application for permanent resident status because of his marriage to Milligan. Although the marriage had ended, he claimed that a previous marriage was sufficient to support his application. The Immigration Judge rejected this claim, concluding that the immediate availability of an immigrant visa was a necessary condition to respondent’s application. Since Milligan had withdrawn her petition for an immigrant visa before the INS had acted on it, respondent was ineligible for permanent resident status.
  Respondent appealed the decision to the Board of Immigration Appeals. For the first time, he raised the claim that the INS was estopped from denying his application because of its “unreasonable delay.” He argued that the “failure to act was not only unreasonable, unfair and unjust but also an abuse of governmental process if the delay was deliberate.” Record 44. The Board rejected respondent’s claim. It found “no evidence of any ‘affirmative misconduct’” and no basis for an equitable estoppel. Id., at 4.
  Respondent sought review of the Board’s decision in the Court of Appeals for the Ninth Circuit. The Court of Appeals reversed, holding that “[t]he unexplained failure of the INS to act on the visa petition for an eighteen-month period prior to the petitioner’s withdrawal. . . was affirmative misconduct by the INS.” Miranda v. INS, 638 F. 2d 83, 84 (1980). We granted certiorari, vacated the judgment of the Court of Appeals, and remanded the case for further consideration in light of Schweiker v. Hansen, 450 U. S. 785 (1981). 454 U. S. 808 (1981).
  On remand, the Court of Appeals adhered to its earlier decision. 673 F. 2d 1105 (1982) (per curiam). It found Hansen inapplicable for three reasons. First, the Government’s conduct in Hansen had not risen to the level of affirmative misconduct. In this case, however, affirmative misconduct was established by the INS’s unexplained delay in processing respondent’s application. Second, although the private party in Hansen subsequently had been able to correct the Government’s error, the INS’s error here inflicted irrevocable harm on respondent. Finally, unlike the private party in Hansen who sought to recover from the public treasury, respondent was seeking only to become a permanent resident — a result that would entail no burden on the public fisc. The Court of Appeals determined that “the Supreme Court’s conclusion that the government was not estopped in Hansen neither compels nor suggests the same conclusion here.” 673 F. 2d, at 1106.
  In Hansen, we did not consider whether estoppel will lie against the Government when there is evidence of affirmative misconduct. We found that a Government official’s misstatement to an applicant for federal insurance benefits, conceded to be less than affirmative misconduct, did not justify allowing the applicant to collect retroactive benefits from the public treasury. See 450 U. S., at 788-789. Although Hansen involved estoppel in the context of a claim against the public treasury, we observed that “[i]n two cases involving denial of citizenship, the Court has declined to decide whether even ‘affirmative misconduct’ would estop the Government from denying citizenship, for in neither case was ‘affirmative misconduct’ involved.” Id., at 788.
  The Court of Appeals thus correctly considered whether, as an initial matter, there ^was a showing of affirmative misconduct. See INS v. Hibi, 414 U. S. 5, 8-9 (1973) (per curiam); Montana v. Kennedy, 366 U. S. 308, 314-315 (1961). Hibi and Montana indicate, however, that the Court of Appeals erred in determining that the evidence in this case established affirmative misconduct. In Montana, a Government official had incorrectly informed the petitioner’s mother that she was unable to return to the United States because she was pregnant. The Court found that the official’s misstatement “falls far short of misconduct such as might prevent the United States from relying on petitioner’s foreign birth” as a basis for denying him citizenship. 366 U. S., at 314-315. In Hibi, Congress had exempted aliens serving in the United States Armed Forces from certain requirements normally imposed on persons seeking naturalization. We found that neither the Government’s failure to publicize fully the rights accorded by Congress nor its failure to make an authorized naturalization representative available to aliens serving outside of the United States estopped the Government from rejecting respondent’s untimely application for naturalization. See 414 U. S., at 8-9.
  Unlike Montana and Hibi, where the Government’s error was clear, the evidence that the Government failed to fulfill its duty in this case is at best questionable. The only indication of negligence is the length of time that the INS took to process respondent’s application. Although the time was indeed long, we cannot say in the absence of evidence to the contrary that the delay was unwarranted. Cf. Citizens to Preserve Overton Park, Inc. v. Volpe, 401 U. S. 402, 415 (1971) (presumption of regularity supports official act of public officer); United States v. Chemical Foundation, Inc., 272 U. S. 1, 14-15 (1926) (same). Both the number of the applications received by the INS and the need to investigate their validity may make it difficult for the agency to process an application as promptly as may be desirable. Even if the INS arguably was negligent in not acting more expeditiously, its conduct was not significantly different from that in Montana and Hibi. Nor is the harm to respondent different. Montana and Hibi make clear that neither the Government’s conduct nor the harm to the respondent is sufficient to estop the Government from enforcing the conditions imposed by Congress for residency in this country.
  The final distinction drawn by the Court of Appeals between this case and Hansen is unpersuasive. It is true that Hansen relied on a line of cases involving claims against the public treasury. But there was no indication that the Government would be estopped in the absence of the potential burden on the fisc. An increasingly important interest, implicating matters of broad public concern, is involved in cases of this kind. Enforcing the immigration laws, and the conditions for residency in this country, is becoming more difficult. See n. 4, swpra. Moreover, the INS is the agency primarily charged by Congress to implement the public policy underlying these laws. See, e. g., INS v. Jong Ha Wang, 450 U. S. 139, 144-145 (1981) (per curiam); Hibi, supra, at 8. Appropriate deference must be accorded its decisions.
  This case does not require us to reach the question we reserved in Hibi, whether affirmative misconduct in a particular case would estop the Government from enforcing the immigration laws. Proof only that the Government failed to process promptly an application falls far short of establishing such conduct. Accordingly, we grant the petition for certio-rari and reverse the judgment of the Court of Appeals.
  It is so ordered.
  Section 201(b) of the Immigration and Nationality Act of 1952 provides for the admission of immigrants who are immediate relatives of United States citizens. 66 Stat. 175, as amended, 8 U. S. C. § 1151(b).
  Section 245(a) provides that the status of an alien who was admitted into the United States “may be adjusted by the Attorney General, in his discretion and under such regulations as he may prescribe, to that of an alien lawfully admitted for permanent residence if (1) the alien makes an application for such adjustment, (2) the alien is eligible to receive an immigrant visa and is admissible to the United States for permanent residence, and (3) an immigrant visa is immediately available to him at the time his application is filed.” 66 Stat. 217, as amended, 8 U. S. C. § 1255(a).
  The INS has maintained consistently that the 18-month delay was reasonable because of the need to investigate the validity of respondent’s marriage. Because the issue of estoppel was raised initially on appeal, the parties were unable to develop any factual record on the issue.
  In 1976, the year in which Milligan filed her petition on behalf of respondent, some 206,319 immediate-relative petitions were filed. See INS Ann. Rep. 11 (1976). The Service has noted: “In dealing with these petitions, an inordinate amount of fraud, particularly in relation to claimed marriages, has been uncovered. . . . For a fee, partners are provided and marriages contracted to establish eligibility under the statutes for visa issuance benefits.” Ibid. We cannot discount the need for careful investigation by the INS that these petitions demand.
choices: U.S. Court of Customs and Patent Appeals U.S. Court of International Trade U.S. Court of Claims, Court of Federal Claims U.S. Court of Military Appeals, renamed as Court of Appeals for the Armed Forces U.S. Court of Military Review U.S. Court of Veterans Appeals U.S. Customs Court U.S. Court of Appeals, Federal Circuit U.S. Tax Court Temporary Emergency U.S. Court of Appeals U.S. Court for China U.S. Consular Courts U.S. Commerce Court Territorial Supreme Court Territorial Appellate Court Territorial Trial Court Emergency Court of Appeals Supreme Court of the District of Columbia Bankruptcy Court U.S. Court of Appeals, First Circuit U.S. Court of Appeals, Second Circuit U.S. Court of Appeals, Third Circuit U.S. Court of Appeals, Fourth Circuit U.S. Court of Appeals, Fifth Circuit U.S. Court of Appeals, Sixth Circuit U.S. Court of Appeals, Seventh Circuit U.S. Court of Appeals, Eighth Circuit U.S. Court of Appeals, Ninth Circuit U.S. Court of Appeals, Tenth Circuit U.S. Court of Appeals, Eleventh Circuit U.S. Court of Appeals, District of Columbia Circuit (includes the Court of Appeals for the District of Columbia but not the District of Columbia Court of Appeals, which has local jurisdiction) Alabama Middle U.S. District Court Alabama Northern U.S. District Court Alabama Southern U.S. District Court Alaska U.S. District Court Arizona U.S. District Court Arkansas Eastern U.S. District Court Arkansas Western U.S. District Court California Central U.S. District Court California Eastern U.S. District Court California Northern U.S. District Court California Southern U.S. District Court Colorado U.S. District Court Connecticut U.S. District Court Delaware U.S. District Court District Of Columbia U.S. District Court Florida Middle U.S. District Court Florida Northern U.S. District Court Florida Southern U.S. District Court Georgia Middle U.S. District Court Georgia Northern U.S. District Court Georgia Southern U.S. District Court Guam U.S. District Court Hawaii U.S. District Court Idaho U.S. District Court Illinois Central U.S. District Court Illinois Northern U.S. District Court Illinois Southern U.S. District Court Indiana Northern U.S. District Court Indiana Southern U.S. District Court Iowa Northern U.S. District Court Iowa Southern U.S. District Court Kansas U.S. District Court Kentucky Eastern U.S. District Court Kentucky Western U.S. District Court Louisiana Eastern U.S. District Court Louisiana Middle U.S. District Court Louisiana Western U.S. District Court Maine U.S. District Court Maryland U.S. District Court Massachusetts U.S. District Court Michigan Eastern U.S. District Court Michigan Western U.S. District Court Minnesota U.S. District Court Mississippi Northern U.S. District Court Mississippi Southern U.S. District Court Missouri Eastern U.S. District Court Missouri Western U.S. District Court Montana U.S. District Court Nebraska U.S. District Court Nevada U.S. District Court New Hampshire U.S. District Court New Jersey U.S. District Court New Mexico U.S. District Court New York Eastern U.S. District Court New York Northern U.S. District Court New York Southern U.S. District Court New York Western U.S. District Court North Carolina Eastern U.S. District Court North Carolina Middle U.S. District Court North Carolina Western U.S. District Court North Dakota U.S. District Court Northern Mariana Islands U.S. District Court Ohio Northern U.S. District Court Ohio Southern U.S. District Court Oklahoma Eastern U.S. District Court Oklahoma Northern U.S. District Court Oklahoma Western U.S. District Court Oregon U.S. District Court Pennsylvania Eastern U.S. District Court Pennsylvania Middle U.S. District Court Pennsylvania Western U.S. District Court Puerto Rico U.S. District Court Rhode Island U.S. District Court South Carolina U.S. District Court South Dakota U.S. District Court Tennessee Eastern U.S. District Court Tennessee Middle U.S. District Court Tennessee Western U.S. District Court Texas Eastern U.S. District Court Texas Northern U.S. District Court Texas Southern U.S. District Court Texas Western U.S. District Court Utah U.S. District Court Vermont U.S. District Court Virgin Islands U.S. District Court Virginia Eastern U.S. District Court Virginia Western U.S. District Court Washington Eastern U.S. District Court Washington Western U.S. District Court West Virginia Northern U.S. District Court West Virginia Southern U.S. District Court Wisconsin Eastern U.S. District Court Wisconsin Western U.S. District Court Wyoming U.S. District Court Louisiana U.S. District Court Washington U.S. District Court West Virginia U.S. District Court Illinois Eastern U.S. District Court South Carolina Eastern U.S. District Court South Carolina Western U.S. District Court Alabama U.S. District Court U.S. District Court for the Canal Zone Georgia U.S. District Court Illinois U.S. District Court Indiana U.S. District Court Iowa U.S. District Court Michigan U.S. District Court Mississippi U.S. District Court Missouri U.S. District Court New Jersey Eastern U.S. District Court (East Jersey U.S. District Court) New Jersey Western U.S. District Court (West Jersey U.S. District Court) New York U.S. District Court North Carolina U.S. District Court Ohio U.S. District Court Pennsylvania U.S. District Court Tennessee U.S. District Court Texas U.S. District Court Virginia U.S. District Court Norfolk U.S. District Court Wisconsin U.S. District Court Kentucky U.S. Distrcrict Court New Jersey U.S. District Court California U.S. District Court Florida U.S. District Court Arkansas U.S. District Court District of Orleans U.S. District Court State Supreme Court State Appellate Court State Trial Court Eastern Circuit (of the United States) Middle Circuit (of the United States) Southern Circuit (of the United States) Alabama U.S. Circuit Court for (all) District(s) of Alabama Arkansas U.S. Circuit Court for (all) District(s) of Arkansas California U.S. Circuit for (all) District(s) of California Connecticut U.S. Circuit for the District of Connecticut Delaware U.S. Circuit for the District of Delaware Florida U.S. Circuit for (all) District(s) of Florida Georgia U.S. Circuit for (all) District(s) of Georgia Illinois U.S. Circuit for (all) District(s) of Illinois Indiana U.S. Circuit for (all) District(s) of Indiana Iowa U.S. Circuit for (all) District(s) of Iowa Kansas U.S. Circuit for the District of Kansas Kentucky U.S. Circuit for (all) District(s) of Kentucky Louisiana U.S. Circuit for (all) District(s) of Louisiana Maine U.S. Circuit for the District of Maine Maryland U.S. Circuit for the District of Maryland Massachusetts U.S. Circuit for the District of Massachusetts Michigan U.S. Circuit for (all) District(s) of Michigan Minnesota U.S. Circuit for the District of Minnesota Mississippi U.S. Circuit for (all) District(s) of Mississippi Missouri U.S. Circuit for (all) District(s) of Missouri Nevada U.S. Circuit for the District of Nevada New Hampshire U.S. Circuit for the District of New Hampshire New Jersey U.S. Circuit for (all) District(s) of New Jersey New York U.S. Circuit for (all) District(s) of New York North Carolina U.S. Circuit for (all) District(s) of North Carolina Ohio U.S. Circuit for (all) District(s) of Ohio Oregon U.S. Circuit for the District of Oregon Pennsylvania U.S. Circuit for (all) District(s) of Pennsylvania Rhode Island U.S. Circuit for the District of Rhode Island South Carolina U.S. Circuit for the District of South Carolina Tennessee U.S. Circuit for (all) District(s) of Tennessee Texas U.S. Circuit for (all) District(s) of Texas Vermont U.S. Circuit for the District of Vermont Virginia U.S. Circuit for (all) District(s) of Virginia West Virginia U.S. Circuit for (all) District(s) of West Virginia Wisconsin U.S. Circuit for (all) District(s) of Wisconsin Wyoming U.S. Circuit for the District of Wyoming Circuit Court of the District of Columbia Nebraska U.S. Circuit for the District of Nebraska Colorado U.S. Circuit for the District of Colorado Washington U.S. Circuit for (all) District(s) of Washington Idaho U.S. Circuit Court for (all) District(s) of Idaho Montana U.S. Circuit Court for (all) District(s) of Montana Utah U.S. Circuit Court for (all) District(s) of Utah South Dakota U.S. Circuit Court for (all) District(s) of South Dakota North Dakota U.S. Circuit Court for (all) District(s) of North Dakota Oklahoma U.S. Circuit Court for (all) District(s) of Oklahoma Court of Private Land Claims