NFIB Sebelius Roberts

 47

 legitimacy of Congress’’s exercise of the spending power
““thus rests on whether the State voluntarily and knowingly
accepts the terms of the ‘‘contract.'”’ ”  Pennhurst, supra,
at 17. Respecting this limitation is critical to ensuring
that Spending Clause legislation does not undermine the
status of the States as independent sovereigns in our fed-
eral system. That system ““rests on what might at first
seem a counterintuitive insight, that ‘’freedom is enhanced
by the creation of two governments, not one.'”’ ”  Bond, 564
U. S., at ___ (slip op., at 8) (quoting Alden v.  Maine, 527
U. S. 706, 758 (1999)). For this reason, ““the Constitution
has never been understood to confer upon Congress the
ability to require the States to govern according to Con-
gress’’ instructions.”” New York, supra, at 162. Otherwise
the two-government system established by the Framers
would give way to a system that vests power in one central
government, and individual liberty would suffer.

  That insight has led this Court to strike down fed-
eral legislation that commandeers a State’s legislative or
administrative apparatus for federal purposes.  See, e.g.,  
Printz, 521 U. S., at 933 (striking down federal legisla-
tion compelling state law enforcement officers to perform
federally mandated background checks on handgun pur-
chasers); New York, supra, at 174-–175 (invalidating provi –
sions of an Act that would compel a State to either take
title to nuclear waste or enact particular state waste
regulations). It has also led us to scrutinize Spending
Clause legislation to ensure that Congress is not using
financial inducements to exert a “”power akin to undue
influence.”” Steward Machine Co. v. Davis, 301 U. S. 548,
590 (1937). Congress may use its spending power to cre-
ate incentives for States to act in accordance with federal
policies. But when “”pressure turns into compulsion,”” ibid.,
the legislation runs contrary to our system of federalism.
““[T]he Constitution simply does not give Congress the
authority to require the States to regulate.””  New York,

48

505 U. S., at 178.  That is true whether Congress directly
commands a State to regulate or indirectly coerces a State
to adopt a federal regulatory system as its own.

  Permitting the Federal Government to force the States
to implement a federal program would threaten the politi-
cal accountability key to our federal system.  “”[W]here the
Federal Government directs the States to regulate, it may
be state officials who will bear the brunt of public disap-
proval, while the federal officials who devised the regu-
latory program may remain insulated from the electoral
ramifications of their decision.””  Id., at 169.  Spending
Clause programs do not pose this danger when a State has
a legitimate choice whether to accept the federal condi-
tions in exchange for federal funds.  In such a situation,
state officials can fairly be held politically accountable for
choosing to accept or refuse the federal offer.  But when
the State has no choice, the Federal Government can
achieve its objectives without accountability, just as in
New York and Printz. Indeed, this danger is heightened
when Congress acts under the Spending Clause, because
Congress can use that power to implement federal policy it
could not impose directly under its enumerated powers.

 We addressed such concerns in Steward Machine. That
case involved a federal tax on employers that was abated
if the businesses paid into a state unemployment plan that
met certain federally specified conditions.  An employer
sued, alleging that the tax was impermissibly “”driv[ing]
the state legislatures under the whip of economic pressure
into the enactment of unemployment compensation laws
at the bidding of the central government.”” 301 U. S., at
587. We acknowledged the danger that the Federal Gov-
ernment might employ its taxing power to exert a ““power
akin to undue influence”” upon the States.  Id., at 590. But
we observed that Congress adopted the challenged tax and
abatement program to channel money to the States that
would otherwise have gone into the Federal Treasury for