WASHINGTON — The Supreme Court reversed a Montana ruling on Monday that blocked corporations from spending unlimited amounts of money to influence state and municipal elections there, disappointing Massachusetts officials and watchdog groups who fear the decision would lead to local corruption across the country.
Massachusetts was one of 22 states that supported Montana’s challenge to the court’s 2010 Citizens United ruling, which unleashed independent political spending by corporations. More than $158 million has been spent by super PACs and other independent groups on this year’s elections, according to the Center for Responsive Politics, and analysts say $1 billion could be used — much of it from a few wealthy, and at times undisclosed, backers.
“As corrosive as the experience has been so far in the presidential election, the potential impact will be worse at the local level where corporate money is even more powerful,” said William Galvin, secretary of the Commonwealth, citing the potential for casinos, developers, and banks to influence elections. “This is just a troubling decision and we’re going to see that as time goes on.”
The Supreme Court’s majority disagreed. In a 5-to-4 ruling, made without briefing or oral argument, the justices reaffirmed that “political speech does not lose First Amendment protection simply because its source is a corporation.”
On the question of whether Citizens United applies to the Montana law, the majority opinion deemed that “there can be no serious doubt that it does.”
Justice Anthony Kennedy, writing for the majority in the Citizens United case, had said that independent political spending by corporations does not contribute to corruption.
Justice Stephen Breyer and his liberal colleagues — Justices Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan — dissented Monday, saying that “independent expenditures by corporations did in fact lead to corruption or the appearance of corruption in Montana.”
Given Montana’s history and political landscape, Breyer wrote, the state Supreme Court had a “compelling interest” in limiting corporate campaign spending. But since the majority justices were unlikely to change their minds, Breyer essentially said he did not see the point of hearing the case.
Montana has long had strict campaign laws, a vestige of its formative days when mining barons controlled much of the state’s politics.
Some Massachusetts politicians and voter advocacy groups are pushing for a constitutional amendment to reverse the Citizens United decision and are drafting bills to expand state laws on disclosure requirements.
The state Senate will consider a resolution Thursday to call on Congress to begin the constitutional amendment process and to allow state legislatures and Congress to regulate corporate political spending.
“What I’m fearful will happen is corporations decide to spend money in Massachusetts and drown out the voice of ordinary citizens and impact the kind of candidates that get elected,” said Senator James Eldridge, a Democrat from Acton and lead sponsor of the resolution. “There can also be a chilling effect on the kinds of positions elected officials take, including on issues important to their constituents.”
State Attorney General Martha Coakley said Monday that the court’s decision is further evidence for the need to pass a constitutional amendment “to make clear that corporate spending is not considered free speech” — a case she has made to congressional leaders in April, along with attorneys general in 10 other states.
Eldridge and Representative Martha Walz, Democrat of Boston, have also sponsored a bill to increase disclosures by corporations that spend money on state and local elections, which they hope the House and Senate will consider this summer.
The bill would require corporations to disclose such expenditures to shareholders and list in political advertisements they sponsor the names of top contributors, Walz said.
“Our laws need to catch up with the Citizens United decision so voters are aware of who is behind the expenditures and shareholders understand how the company is spending its resources,” Walz said.
The Citizens United ruling did not limit such disclosure requirements, but efforts in Congress to address the issue nationally have been sidelined by partisan divisions.
Until the 2010 ruling, Massachusetts had banned corporate contributions to political activity since 1907.
Other than the organization of four independent PACs, there has been little change in corporate political activity in the state, according to the Massachusetts Office of Campaign and Political Finance.
“In my view, it’s only a question of when it will start, not if it will start,” Walz said.
Avi Green, director of MassVOTE, said it would take just $100,000 for corporations to have a disproportionate impact on local or legislative races. “That’s chicken feed for the state’s largest companies,” he said.
Some who support the Citizens United decision — and Monday’s reaffirmation of it — disagree that corporations would unduly influence elections.
Bradley Smith, a professor at Capital University Law School in Columbus, Ohio, and former member of the Federal Election Commission, said none of the horror stories some said would come out of the 2010 decision have materialized.
“This fear that corporations would basically dictate policy and drive everybody else out, there is no evidence of that,” Smith said, citing higher voter turnout, more competitive races, and the fact that Fortune 500 companies are not dominating politics as reasons why the court should not reconsider Citizens United.
Furthermore, he said, Montana was acting lawless by disregarding it.
“Imagine if a state said, ‘Our crime is so bad, we don’t have to respect habeas corpus anymore or put up with search warrants,’ ” Smith said. “I don’t think we’d take it seriously.”Tracy Jan can be reached at email@example.com. Follow her on Twitter @GlobeTracyJan.