Presumptive Democratic candidate for president Hillary Clinton recently announced, "In my first 30 days as president, I will propose a constitutional amendment to overturn Citizens United and give the American people, all of us, the chance to reclaim our democracy."

This injection of what would be the 28th Amendment into the heart of the presidential race and the top of Clinton's agenda is much more significant than a bid for Bernie Sanders supporters or the checking another progressive agenda box. Instead, the constitutional amendment Clinton calls for is badly needed, has overwhelming cross-partisan support in the country and is much closer to passage and ratification than many realize.

The 2010 Citizens United v. Federal Election Commission is the most well-known of a series of 5-4 Supreme Court decisions that invalidated limits on political spending and declared that spending money to influence elections and policy is a constitutional "free speech" right that may not be limited. Since Citizens United, more than $30 billion has been spent in elections, most of it from a relatively handful of wealthy people, global corporations and some large unions. Beyond election spending, corporations now are using Citizens United to challenge the validity of financial regulation, environmental and energy laws, health care laws, cuts in taxpayer corporate subsidies and more.

By calling for a constitutional amendment to end this dangerous doctrine of special rights for money and corporations, Hillary Clinton may be jumping in front of an on-going parade, but it is a rapidly growing parade of almost all Americans, not only progressives.

More than 75 percent of Republicans, Democrats and independents support a 28th Amendment to overturn Citizens United. If you don't believe polls, believe voters: In Montana and Colorado, citizens passed constitutional amendment ballot initiatives by 75 percent to 25 percent. This past April, 84 percent of voters in Janesville, Wisconsin, approved 28th Amendment resolutions. Janesville is the hometown of Republican Paul Ryan, the speaker of the House, and similar resolutions have passed with similar levels of support in 75 communities in Wisconsin and 700 cities and towns in every region of the country.

New York recently joined 16 other states to call on Congress to pass a 28th Amendment to secure fair elections, equal representation and the rights of Americans to limit spending and contributions in elections. And even Congress is responding. More than 150 House members are cosponsoring a 28th Amendment; 54 Senators voted for the amendment after it cleared the Judiciary Committee in 2014. The same amendment was reintroduced in the Senate with 44 cosponsors.

The growing support for a reforming constitutional amendment reflects a national conflict between two irreconcilable constitutional values, where the Court's Citizens United jurisprudence has left no middle ground: Under Citizens United, we live under principles of oligarchy, where those with more money and access to the power of large corporations get more political representation, less regulation and more say. Under the 28th Amendment, we live under principles of human freedom and equal citizenship, where policy choices are decided in a democratic process among equal human beings. Only one of these constitutional values can prevail, and a constitutional amendment is necessary to decide that question.

Some say we can improve things with more disclosure, publicly financed elections or regulatory steps. Many good reforms have been proposed but no solution or set of policies can paper over the gaping cracks in our national foundation. Sound reform cannot be built on a doctrine of unequal citizenship; on privileged power for corporations and money; and on a nation of passive or angry spectators or "consumers" rather than engaged, responsible citizens.