In a 5-4 ruling that reaffirms the Supreme Court’s position that unrestricted political spending is constitutional, the high court today summarily reversed a lower court ruling upholding a Montana ban on corporate campaign expenditures.

In American Tradition Partnership Inc. v. Bullock, the high court was asked to review a Montana law that banned corporate political spending. That state law was nullified by the court’s 2010 Citizens United v. Federal Election Commission ruling, which rejected long-standing limits on independent corporate and union political spending.

But the state refused to remove its corporate spending ban from the books, inviting a constitutional challenge. The state Supreme Court had sided with Montana, but today the high court summarily reversed that holding. The upshot is that the Montana law is struck.

“The question presented in this case is whether the holding of Citizens United applies to the Montana state law,” wrote the Supreme Court majority, consisting of Chief Justice John Roberts and Justices Samuel Alito, Anthony Kennedy, Antonin Scalia and Clarence Thomas. “There can be no serious doubt that it does.”

In a written dissent, Justice Stephen Breyer echoed the arguments presented by then-Justice John Paul Stevens in his dissent in the Citizens United ruling.

“As Justice Stevens explained, ‘technically independent expenditures can be corrupting in much the same way as direct contributions,’” wrote Breyer, who was joined by Justices Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan.

Senate Minority Leader Mitch McConnell (R-Ky.) hailed the ruling, which he called “an important victory for free speech.” McConnell had filed an amicus brief urging the court to uphold the constitutional challenge to the Montana law. McConnell argued that corporate donations have not underwritten political spending by unrestricted super PACs in this election.

“Clearly, the much-predicted corporate tsunami that critics of Citizens United warned about simply did not occur,” McConnell said in a statement.

Campaign reform advocates deplored the reversal in the Montana case. Numerous amicus briefs had flooded the high court from Members of Congress, state attorneys general and activists arguing that the high court should seize on the Montana case as an opportunity to revisit Citizens United.

“The Supreme Court today has left standing the disastrous Citizens United decision and the enormous damage it is doing to our democracy and political system,” Democracy 21 President Fred Wertheimer said in a statement. Wertheimer and other reform advocates said they will continue to push for anti-corruption measures through legal and legislative channels.