Let’s examine each of those questions:
First, are states required to enforce federal laws and enact regulatory programs that Congress mandates? The answer on both counts is “No.”
In the 1997 case, Printz v. United States, the Supreme Court ruled that the federal government could not command state law enforcement authorities to conduct background checks on prospective handgun purchasers.
In the 1992 case, New York v. United States, the Court ruled that Congress couldn’t require states to enact specified waste disposal regulations.
The second question is more difficult: Can a state impede federal authorities from enforcing their own law if the state deems the law to be unconstitutional. The answer is “No,” although more radical nullification proponents would disagree. They point to the Kentucky and Virginia Resolutions of 1798 and 1799, in which Thomas Jefferson and James Madison asserted a state’s right to nullify the Alien and Sedition Acts.
But consider those resolutions in context: Jefferson and Madison had argued that the states must have the final word because the Constitution had not expressly established an ultimate authority on constitutional matters.
Four years later in Marbury v. Madison, Chief Justice John Marshall resolved that oversight. He wrote: “It is emphatically the province and duty of the judicial department to say what the law is.” Since then, instead of 50 individual states effecting their own views regarding constitutionality, we have one Supreme Court establishing a uniform rule for the entire nation.
The Framers concurred. In Federalist 78, Alexander Hamilton had written: “\ limited constitution … can be preserved in practice no other way than through the medium of courts of justice, whose duty it must be to declare all acts contrary to the manifest tenor of the constitution void.” Madison shared that view. He wrote: “(I)ndependent tribunals … will be an impenetrable bulwark against every assumption of power in the legislative or executive.”
Even before Marbury, the Virginia General Assembly had passed Madison’s Report of 1800. It acknowledged that states can declare federal laws unconstitutional; but the declaration would have no legal effect unless the courts agreed. Here’s what Madison wrote: State “declarations … are expressions of opinion, (intended only for) exciting reflection. The expositions of the judiciary, on the other hand, are carried into immediate effect.”
Madison also published Notes on Nullification in 1834. There, he wrote that an individual state cannot unilaterally invalidate a federal law. That process requires collective action by the states. Similarly, Jefferson’s Kentucky Resolutions had described nullification as an act by “the several states” that formed the Constitution.
Moreover, seven states rejected resolutions similar to Virginia’s and Kentucky’s; six states passed alternate resolutions holding that constitutionality was for courts to decide; four states took no action. No other state went along with Virginia or Kentucky.
Since then, nullification attempts have failed on three occasions: In 1828, South Carolina tried to nullify two national tariffs. President Andrew Jackson proclaimed nullification to be treason; Congress authorized Jackson to send troops, and the state backed down. In 1859, the Supreme Court rejected nullification in Ableman v. Booth.
Booth had frustrated recapture of a slave in violation of the Fugitive Slave Act. Wisconsin’s Supreme Court held the act unconstitutional, but the U.S. Supreme Court reinstated the conviction. In 1958, after southern states refused to integrate their schools, the Supreme Court in Cooper v. Aaron held that nullification “is not a constitutional doctrine … it is illegal defiance of constitutional authority.”
Fans of nullification count on the states to check federal tyranny. But sometimes it cuts the other way; states are also tyrannical. Indeed, if state and local governments could invalidate federal law, Virginia would have continued its ban on inter‐racial marriages; Texas might still be jailing gay people for consensual sex; and constructive gun bans would remain in effect in Chicago and elsewhere.
Finally, question #3: If a state deems a federal law to be unconstitutional, what’s the proper remedy? The answer is straightforward. Because the Supreme Court is the ultimate authority, the remedy is a lawsuit challenging the constitutionality of the suspect federal regulation or statute.