NFIB Sebelius Roberts

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powers. The Court of Appeals unanimously held that the
Medicaid expansion is a valid exercise of Congress’’s power
under the Spending Clause.  U. S. Const., Art. I, §8, cl. 1.
And the court rejected the States’’ claim that the threat-
ened loss of all federal Medicaid funding violates the
Tenth Amendment by coercing them into complying with
the Medicaid expansion. 648 F. 3d, at 1264, 1268.

  We granted certiorari to review the judgment of the
Court of Appeals for the Eleventh Circuit with respect to
both the individual mandate and the Medicaid expansion.
565 U. S. ___ (2011).  Because no party supports the Elev-
enth Circuit’s holding that the individual mandate can
be completely severed from the remainder of the Affordable
Care Act, we appointed an amicus curiae to defend that
aspect of the judgment below. And because there is a
reasonable argument that the Anti-Injunction Act de-
prives us of jurisdiction to hear challenges to the individ-
ual mandate, but no party supports that proposition, we
appointed an amicus curiae to advance it.2

II

 Before turning to the merits, we need to be sure we have
the authority to do so. The Anti-Injunction Act provides
that “”no suit for the purpose of restraining the assessment
or collection of any tax shall be maintained in any court
by any person, whether or not such person is the per-
son against whom such tax was assessed.””  26 U. S. C.
§7421(a). This statute protects the Government’’s ability
to collect a consistent stream of revenue, by barring litiga-
tion to enjoin or otherwise obstruct the collection of taxes.
Because of the Anti-Injunction Act, taxes can ordinarily be
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2 We appointed H. Bartow Farr III to brief and argue in support of the
Eleventh Circuit’s judgment with respect to severability, and Robert A.
Long to brief and argue the proposition that the Anti-Injunction Act
bars the current challenges to the individual mandate.  565 U. S. ___
(2011). Both amici have ably discharged their assigned responsibilities. 

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challenged only after they are paid, by suing for a refund.
See Enochs v. Williams Packing & Nav. Co., 370 U. S. 1,
7–8 (1962).

  The penalty for not complying with the Affordable Care
Act’’s individual mandate first becomes enforceable in
2014. The present challenge to the mandate thus seeks to
restrain the penalty’s future collection.  Amicus contends
that the Internal Revenue Code treats the penalty as a
tax, and that the Anti-Injunction Act therefore bars this
suit.

  The text of the pertinent statutes suggests otherwise.
The Anti-Injunction Act applies to suits “”for the purpose
of restraining the assessment or collection of any tax.””
§7421(a) (emphasis added).  Congress, however, chose to
describe the “”[s]hared responsibility payment”” imposed on
those who forgo health insurance not as a “”tax,”” but as a
““penalty.””  §§5000A(b), (g)(2).  There is no immediate
reason to think that a statute applying to “”any tax”” would
apply to a “”penalty.””

  Congress’’s decision to label this exaction a “”penalty””
rather than a “”tax”” is significant because the Affordable
Care Act describes many other exactions it creates as
““taxes.”” See Thomas More, 651 F. 3d, at 551.  Where
Congress uses certain language in one part of a statute
and different language in another, it is generally pre-
sumed that Congress acts intentionally. See Russello v.
United States, 464 U. S. 16, 23 (1983).

 Amicus argues that even though Congress did not label
the shared responsibility payment a tax, we should treat it
as such under the Anti-Injunction Act because it functions
like a tax. It is true that Congress cannot change whether
an exaction is a tax or a penalty for constitutional pur-
poses simply by describing it as one or the other.  Congress
may not, for example, expand its power under the Taxing
Clause, or escape the Double Jeopardy Clause’s constraint
on criminal sanctions, by labeling a severe financial pun-