It was former Congressman Barney Frank who best captured the iron grip that cash-dispensing special interests have on American politics. “I can’t be bought,” quipped Frank, spoofing politicians’ ludicrous but straight-faced denials that campaign money influences their actions, “but I sure as hell can be rented.”

American Promise, a Mass­achusetts-based, nonpartisan organization founded to mobilize national support for a constitutional amendment addressing the out-of-control dominance of money over our political system, summarizes the problem in a new report titled “Government of Citizens, Not Money.” According to the report, about $40 billion in campaign cash has been spent determining who will constitute Congress and our state legislatures since 2010 alone, most of it furnished by fewer than 1 percent of Americans. The result is unsurprising. “A wealthy donor class now calls the shots,” the report concludes, “not the people.”

Americans overwhelmingly understand both the extent of the problem and the gravity of its implications. A 2015 New York Times/CBS survey found that 84 percent of them believe that money wields too much influence over American politics. The University of Maryland’s School of Public Policy released a poll just last week finding that 88 percent of Americans — including a whopping 84 percent of Republicans — regard it as either very important or important to “reduc(e) or counterbalanc(e) the influence of big campaign donors, including special interests, corporations and wealthy people, on the Federal government.”

A Congress controlled by those donors, who do not want their influence reduced let alone removed, and a political system diseased with partisan toxicity and encased by gridlock are among the reasons that the widespread acknowledgement of the problem has not translated into real efforts at a solution. But the U.S. Supreme Court’s landmark Citizens United decision in 2010 was a staggering blow to whatever hopes for campaign finance reform had survived decades of congressional resistance. By a 5-4 vote, the court ruled that the First Amendment’s free speech clause protected mega-wealthy individuals and behemoth corporations from restrictions on their ability to plow unlimited cash into supporting or opposing candidates for office, effectively bestowing its blessing on drowning out everyone else’s political speech.

American Promise has launched a nationwide campaign to pass a 28th Amendment to the Constitution, one that would override Citizens United. Leveraging networks of volunteers and a growing list of big-name supporters, it is focused on ground-up organizing around the country aimed at winning the required approval of two-thirds of Congress and three-quarters of the nation’s state legislatures. Its president, former Massachusetts Assistant Attorney General Jeff Clements, is clear-eyed about the daunting task but buoyed by what he terms the “cross-partisan” support for the amendment.

He may be on to something. An August 2017 poll taken for the Center for Public Integrity found that 48 percent of Americans disagreed with Citizens United, while only 30 percent supported it, and that a plurality, even of Republicans, opposed it. Last week’s University of Maryland survey provides even more specific, more dramatic support for Clements’ optimism. Three-quarters of all Americans favor the constitutional amendment that he and his colleagues are working to bring about, including 66 percent of all Republicans.

Clements rejects the argument that by leveling the playing field to permit the voices of ordinary citizens to be heard in political campaigns, reasonable restrictions on spending undercut free speech. “This is strengthening the First Amendment, not weakening it,” he says, comparing it to Town Meeting limitations on how long people are permitted to speak that are imposed to ensure that everyone who wants to speak has the opportunity to do so.

Clements has been crisscrossing the country, working to get resolutions endorsing the constitutional amendment on state ballots. He is convinced by the bipartisan support he is finding that it will eventually carry the day. “Americans always do the right thing,” he says with a smile, invoking a quote popularly attributed to Winston Churchill, “after exhausting all other possibilities.”

Jeffrey Robbins is a Boston attorney and former U.S. delegate to the United Nations Human Rights Commission.