the District Court's finding that it was unreasonable for respondent to rely on Travelers' advice, concluding instead that respondent acted reasonably because the relevant regulation had no clear meaning and respondent had no source other than Travelers to which it could turn for advice.

II

Estoppel is an equitable doctrine invoked to avoid injustice in particular cases. While a hallmark of the doctrine is its flexible application, certain principles are tolerably clear:

"If one person makes a definite misrepresentation of fact to another person having reason to believe that the other will rely upon it and the other in reasonable reliance upon it does an act . . . the first person is not entitled

"(b) to regain property or its value that the other acquired by the act, if the other in reliance upon the misrepresentation and before discovery of the truth has so changed his position that it would be unjust to deprive him of that which he thus acquired." Restatement (Second) of Torts § 894(1) (1979).8

Thus, the party claiming the estoppel must have relied on its adversary's conduct "in such a manner as to change his position for the worse, "9 and that reliance must have been reasonable in that the party claiming the estoppel did not know nor should it have known that its adversary's conduct was misleading. 10 See Wilber National Bank v. United States, 294 U. S. 120, 124-125 (1935).

See also Restatement (Second) of Agency § 8B (1958).

93 J. Pomeroy, Equity Jurisprudence § 805, p. 192 (S. Symons ed. 1941); see also id., § 812.

10 "The truth concerning these material facts must be unknown to the other party claiming the benefit of the estoppel, not only at the time of the conduct which amounts to a representation or concealment, but also at the time when that conduct is acted upon by him. If, at the time when he

When the Government is unable to enforce the law because the conduct of its agents has given rise to an estoppel, the interest of the citizenry as a whole in obedience to the rule of law is undermined. It is for this reason that it is well settled that the Government may not be estopped on the same terms as any other litigant." Petitioner urges us to expand this principle into a flat rule that estoppel may not in any circumstances run against the Government. We have left the issue open in the past,12 and do so again today. Though the arguments the Government advances for the rule are substantial, we are hesitant, when it is unnecessary to decide this case, to say that there are no cases in which the public interest in ensuring that the Government can enforce the law free from

12

acted, such party had knowledge of the truth, or had the means by which with reasonable diligence he could acquire the knowledge so that it would be negligence on his part to remain ignorant by not using those means, he cannot claim to have been misled by relying upon the representation or concealment." Id., § 810, at 219 (footnote omitted).

11

See, e. g., INS v. Hibi, 414 U. S. 5, 8 (1973) (per curiam); Federal Crop Insurance Corp. v. Merrill, 332 U. S. 380, 383 (1947).

12 See INS v. Miranda, 459 U. S. 14, 19 (1982) (per curiam); Schweiker v. Hansen, 450 U. S. 785, 788 (1981) (per curiam); Montana v. Kennedy, 366 U. S. 308, 315 (1961). In fact, at least two of our cases seem to rest on the premise that when the Government acts in misleading ways, it may not enforce the law if to do so would harm a private party as a result of governmental deception. See United States v. Pennsylvania Industrial Chemical Corp., 411 U. S. 655, 670–675 (1973) (criminal defendant may assert as a defense that the Government led him to believe that its conduct was legal); Moser v. United States, 341 U. S. 41 (1951) (applicant cannot be deemed to waive right to citizenship on the basis of a form he signed when he was misled as to the effect signing would have on his rights). See also Kaiser Aetna v. United States, 444 U. S. 164, 178–180 (1979); Santobello v. New York, 404 U. S. 257 (1971); Branson v. Wirth, 17 Wall. 32, 42 (1873). This principle also underlies the doctrine that an administrative agency may not apply a new rule retroactively when to do so would unduly intrude upon reasonable reliance interests. See NLRB v. Bell Aerospace Co., 416 U. S. 267, 295 (1974); Atchison, T. & S. F. R. Co. v. Wichita Bd. of Trade, 412 U. S. 800, 807-808 (1973) (plurality opinion); SEC v. Chenery Corp., 332 U. S. 194, 203 (1947).

estoppel might be outweighed by the countervailing interest of citizens in some minimum standard of decency, honor, and reliability in their dealings with their Government. 13 But however heavy the burden might be when an estoppel is asserted against the Government, the private party surely cannot prevail without at least demonstrating that the traditional elements of an estoppel are present. We are unpersuaded that that has been done in this case with respect to either respondent's change in position or its reliance on Travelers' advice.

III

To analyze the nature of a private party's detrimental change in position, we must identify the manner in which reliance on the Government's misconduct has caused the private citizen to change his position for the worse. In this case the consequences of the Government's misconduct were not entirely adverse. Respondent did receive an immediate benefit as a result of the double reimbursement. Its detriment is the inability to retain money that it should never have received in the first place. Thus, this is not a case in which the respondent has lost any legal right, either vested or contin

13 See generally St. Regis Paper Co. v. United States, 368 U. S. 208, 229 (1961) (Black, J., dissenting) ("Our Government should not by picayunish haggling over the scope of its promise, permit one of its arms to do that which, by any fair construction, the Government has given its word that no arm will do. It is no less good morals and good law that the Government should turn square corners in dealing with the people than that the people should turn square corners in dealing with their government"); Federal Crop Insurance Corp. v. Merrill, 332 U. S., at 387-388 (Jackson, J., dissenting) ("It is very well to say that those who deal with the Government should turn square corners. But there is no reason why the square corners should constitute a one-way street"); Brandt v. Hickel, 427 F. 2d 53, 57 (CA9 1970) ("To say to these appellants, "The joke is on you. shouldn't have trusted us,' is hardly worthy of our great government"); Menges v. Dentler, 33 Pa. 495, 500 (1859) ("Men naturally trust in their government, and ought to do so, and they ought not to suffer for it"). See also Giglio v. United States, 405 U. S. 150, 154–155 (1972).

You

gent, or suffered any adverse change in its status." When a private party is deprived of something to which it was entitled of right, it has surely suffered a detrimental change in its position. Here respondent lost no rights but merely was induced to do something which could be corrected at a later time. 15

There is no doubt that respondent will be adversely affected by the Government's recoupment of the funds that it has already spent. It will surely have to curtail its operations and may even be forced to seek relief from its debts through bankruptcy. However, there is no finding as to the extent of the likely curtailment in the volume of services provided by respondent, much less that respondent will reduce its activities below the level that obtained when it was first advised that the double reimbursement was proper. Respondent may need an extended period of repayment or other modifications in the recoupment process if it is to continue to operate, but questions concerning the Government's method of enforcing collection are not before us. The question is whether the Government has entirely forfeited its right to the money.

A for-profit corporation could hardly base an estoppel on the fact that the Government wrongfully allowed it the interest-free use of taxpayers' money for a period of two or three years, enabling it to expand its operation. 16 No more can respondent claim any right to expand its services to levels greater than those it would have provided had the error never occurred. Curtailment of operation does not justify an estoppel when by respondent's own account-the expansion

14 This case is, therefore, plainly distinguishable from Moser v. United States, 341 U. S. 41 (1951), in which the petitioner "was led to believe that he would not thereby lose his rights to citizenship." Id., at 46.

15 See Schweiker v. Hansen, 450 U. S., at 789 (per curiam).

16 See United States v. Stewart, 311 U. S. 60, 70 (1940); Sutton v. United States, 256 U. S. 575 (1921); Pine River Logging Co. v. United States, 186 U. S. 279, 291 (1902); Hart v. United States, 95 U. S. 316 (1877). See also Automobile Club v. Commissioner, 353 U. S. 180 (1957).

of its operation was achieved through unlawful access to governmental funds. And even if there will be a reduction below the service provided by respondent prior to its receipt of CETA funds, the record does not foreclose the possibility that the aggregate advantages to the community stemming from respondent's use of the money have more than offset the actual hardship associated with now being required to restore these funds. Respondent cannot raise an estoppel without proving that it will be significantly worse off than if it had never obtained the CETA funds in question.

IV

Justice Holmes wrote: "Men must turn square corners when they deal with the Government.' Rock Island, A. & L. R. Co. v. United States, 254 U. S. 141, 143 (1920). This observation has its greatest force when a private party seeks to spend the Government's money. Protection of the public fisc requires that those who seek public funds act with scrupulous regard for the requirements of law; respondent could expect no less than to be held to the most demanding standards in its quest for public funds. This is consistent with the general rule that those who deal with the Government are expected to know the law and may not rely on the conduct of Government agents contrary to law."7

17 "Whatever the form in which the Government functions, anyone entering into an arrangement with the Government takes the risk of having accurately ascertained that he who purports to act for the Government stays within the bounds of his authority. The scope of this authority may be explicitly defined by Congress or be limited by delegated legislation, properly exercised through the rule-making power. And this is so even though, as here, the agent himself may have been unaware of the limitations upon his authority." Federal Crop Insurance Corp. v. Merrill, 332 U. S., at 384.

See United States v. California, 332 U. S. 19, 39–40 (1947); United States v. Stewart, 311 U. S., at 70; United States v. San Francisco, 310 U. S. 16, 31-32 (1940); Wilber National Bank v. United States, 294 U. S. 120, 123-124 (1935); Utah v. United States, 284 U. S. 534, 545-546 (1932); Jeems Bayou Fishing & Hunting Club v. United States, 260 U. S. 561, 564