AUGUSTA, Maine — Republican state Sen. Edward Youngblood of Brewer and Democratic state Sen. Geoff Gratwick of Bangor joined forces Tuesday to endorse a constitutional amendment to overturn the Supreme Court’s 2010 ruling that equates campaign donations to free speech protected by the First Amendment.

The two state senators attended a State House rally Tuesday morning to mark the third anniversary of the high court’s decision in Citizens United v. the Federal Election Commission. That ruling prevents the federal government from enacting laws that limit independent campaign expenditures by groups such as corporations and unions. Maine Citizens for Clean Elections, which sponsored Tuesday’s rally, is part of a national campaign to compel Congress to amend the U.S. Constitution in a way that would rein in outside campaign spending.

“Voters of all backgrounds are calling for a U.S. Constitution amendment that would allow us to regulate the raising and spending of campaign funds to stop the unlimited flow of secret money into our democratic process,” Andrew Bossie, executive director of MCCE, told a crowd of more than 50 people, some of whom rode a bus to the rally. Many held signs that read “End corporate personhood.”

A constitutional amendment would require ratification by voters in three-quarters (38) of the 50 states.

The MCCE’s leaders say they’ve collected more than 11,000 postcards from Maine voters who support amending the U.S. Constitution to reduce the influence of independent political action committees that aren’t held to the same rules as candidates or committees directly affiliated with candidates. They planned to present the postcards to Maine legislators, using the opportunity to urge them to support the Maine Clean Election Act. In 1996, Maine voters approved the act, which provides public financing for legislative and gubernatorial elections.

Gov. Paul LePage proposes to cut $4 million for public campaign financing in his budget for the biennium that begins July 1. That doesn’t sit well with Youngblood, Gatwick and other legislators who attended Tuesday’s event, including Rep. Jeffrey Evangelos, I-Friendship, who also has submitted legislation that would put Maine on record as supporting an amendment to overturn Citizens United.

Youngblood said he understands the challenge LePage faces in balancing the budget, but that the governor’s proposal to cut $4 million from the Clean Election fund runs counter to what his constituents tell him they want.

“A lot of my constituents are part of the silent majority and, when you talk to them on their doorstep, they are happy that you’re a Clean Election candidate,” the Republican senator said.

A former member of the Maine Commission on Governmental Ethics and Election Practices, which oversees public campaign financing, Youngblood supports a constitutional amendment to overturn Citizens United and has submitted legislation to strengthen Maine’s Clean Election Act. That bill has yet to receive a legislative document number, but Youngblood said Tuesday that he expects it will draw Democrats, Republicans and independents as co-sponsors.

“There has to be a way to secure First Amendment rights to speech and still control the amount of dollars spent on campaigns,” he said. “It should be plain to everyone after the election we’ve just had, which broke records for spending, that the system isn’t getting better.”

Gatwick drew attention to the negative impact outside contributions had on his 2012 race against incumbent Republican Sen. Nichi Farnham. Both ran publicly funded campaigns, but Democratic and Republican party groups that targeted the Senate District 32 race as a key to control of the Senate spent more than $450,000 on the contest, making it the most expensive legislative campaign in Maine.

“I like to think that I won because of my message and ideas,” Gratwick told the crowd Tuesday. “But it was hard to tell whether we were having an election or an auction in Bangor last November.”

Gratwick said the experience left him “deeply angered” by the amount of money poured into the race by groups that had no interest in local issues and no connection to the people of District 32.

Echoing other speakers Tuesday, he said, “Elections are in danger of no longer being democratic but rather a way of concentrating power in the hands of the wealthy.”

Bossie said that his group continues to lobby Maine’s congressional delegation to support a resolution calling for the constitutional amendment. U.S. Rep. Chellie Pingree, a Democrat who represents Maine’s 1st Congressional District, last week reintroduced legislation designed to create a federal public campaign financing system similar to Maine’s.

U.S. Sen. Angus King, I-Maine, criticized the Citizens United decision regularly during his campaign. Bossie said Tuesday that MCCE continues to talk with U.S. Sen. Susan Collins, R-Maine, and U.S. Rep. Mike Michaud, a Democrat who represents Maine’s 2nd District, about campaign finance reform.

Scott Thistle, political editor of the Lewiston Sun Journal, contributed to this report.