The U.S. Senate is expected to vote Monday on a constitutional amendment that would effectively overturn the Supreme Court's decision in Citizens United. The bill, sponsored by Senator Tom Udall (D-New Mexico), "grants Congress and the states the power to regulate the raising and spending of money and in-kind equivalents with respect to federal and state elections, respectively."

“This is a historic moment,” said Marge Baker, executive vice president at People For the American Way, which has been one of the leaders of the push for a constitutional amendment. “The Citizens United decision came just four and a half years ago, and now the Senate is about to vote on an amendment to overturn it. Americans are fed up with the staggering amounts of money flooding elections. With this level of public support for taking money out of politics, it’s clear that this is just the beginning of the push for an amendment.”

Because it would amend the U.S. Constitution, the proposal requires a two-thirds majority to pass. It would then have to pass in the House by the same majority and be ratified by three-fourths of the state legislatures. According to Public Citizen, 50 senators have indicated their support for the amendment.

A poll of 800 likely voters commissioned by Public Citizen and conducted by two polling firms, one Democratic and one Republican, recently found that by a 2-1 margin, voters provided with a short description of the amendment are in favor of it.

“It’s time for Congress to act on the people’s demand for a constitutional amendment to overturn Citizens United and restore our democracy,” said Robert Weissman, president of Public Citizen, in a statement. “This poll shows that the public, including Republican voters, forcefully rejects arguments from Senator Mitch McConnell and Senator Ted Cruz in defense of the status quo.”

McConnell, Cruz, and other Republican officials have claimed that constraints on campaign spending amount to an assault on free speech. Earlier this summer, ACLU leaders bolstered that argument, saying they opposed the Udall amendment on the grounds that it would "severely limit the First Amendment, lead directly to government censorship of political speech and result in a host of unintended consequences that would undermine the goals the amendment has been introduced to advance — namely encouraging vigorous political dissent and providing voice to the voiceless, which we, of course, support."

But on Thursday, a group of former ACLU leaders struck back in a letter to several high-ranking senators. "While, as present and former leaders of the ACLU, we take no position in this letter on whether a constitutional amendment is the most appropriate way to pursue campaign finance reform," the letter reads, "we believe that the current leadership of the National ACLU has endorsed a deeply contested and incorrect reading of the First Amendment as a rigid deregulatory strait jacket that threatens the integrity of American democracy."

Organizations like Public Citizen, MoveOn, and People for the American Way are encouraging voters to contact their senators and urge them to support the amendment. In Portsmouth, New Hampshire on Thursday, a group of about 25 activists delivered a petition with 10,500 signatures to the office of U.S. Senator Kelly Ayotte (R-NH); similar actions took place across the country.