"From our earliest cases, we have recognized that equitable
estoppel will not lie against the Government as it lies
against private litigants. In Lee v. Munroe and Thornton, 7
Cranch 366 (1813), we held that the Government could not be
bound by the mistaken representations of an agent unless it
were clear that the representations were within the scope of
the agent's authority. In The Floyd Acceptances, 7 Wall.
666 (1869), we held that the Government could not be
compelled to honor bills of exchange issued by the Secretary
of War where there was no statutory authority for the
issuance of the bills. In Utah Power and Light Co. v. United
States[1917] USSC 66; , 243 US 389, 408-409 (1917), we dismissed the
argument that unauthorized representations by agents of the
Government estopped the United States to prevent erection of
power houses and transmission lines across a public forest
in violation of a statute: 'Of this it is enough to say that
the United States is neither bound nor estopped by acts of
its officers or agents in entering into an arrangement or
agreement to do or cause to be done what the law does not
sanction or permit.'
... Despite the clarity of these earlier decisions, dicta in
our more recent cases have suggested the possibility that
there might be some situation in which estoppel against the
Government could be appropriate.
...
The Solicitor General proposes to remedy the present
confusion in this area of the law with a sweeping rule. As
it has in the past, the Government asks us to adopt 'a flat
rule that estoppel may not in any circumstances run against
the Government.' Community Health Services, supra (467
U.S.), at 60. The Government bases its broad rule first
upon the doctrine of sovereign immunity. Noting that the
'United States, as sovereign, is immune from suit save as it
consents to be sued,' United States v. Mitchell, 445 US
535, 538 (1980), petitioner asserts that the courts are
without jurisdiction to entertain a suit to compel the
Government to act contrary to a statute, no matter what the
context or circumstances. See Brief for Petitioner 12-13.
Petitioner advances as a second basis for this rule the
doctrine of separation of powers. Petitioner contends that
to recognize estoppel based on the misrepresentations of
Executive Branch officials would give those
misrepresentations the force of law, and thereby invade the
legislative province reserved to Congress. This rationale,
too, supports the petitioner's contention that estoppel may
never justify an order requiring executive action contrary
to a relevant statute, no matter what statute or what facts
are involved.
We have recognized before that the 'arguments the Government
advances for the rule are substantial.' Community Health
Services, supra, at 60. And we agree that this case should
be decided under a clearer form of analysis than 'we will
know an estoppel when we see one.' Hansen, supra, at 792
(Marshall, J, dissenting). But it remains true that we
need not embrace a rule that no estoppel will lie against
the Government in any case in order to decide this case. We
leave for another day whether an estoppel claim could ever
succeed against the Government. A narrower ground of
decision is sufficient to address the type of suit presented
here, a claim for payment of money from the Public Treasury
contrary to a statutory appropriation."