WORCESTER - Over the course of American history, constitutional amendments often bubble up in clusters as a response to a turbulent period, Jeffrey Clements told the local chapter of the League of Women Voters Wednesday night.

We could be living through one of those times right now, he added, predicting that 10 to 15 years from now the country might be able to look back and see that two or three amendments were added to the U.S. Constitution during this modern era.

Mr. Clements, author of "Corporations are Not People" and founder of American Promise, is interested in getting one amendment in particular passed. His organization is leading efforts nationwide to drum up interest in a 28th amendment that would reverse the "Citizens United" U.S. Supreme Court ruling that political spending is a form of free speech.

He talked for more than an hour Wednesday at the First Baptist Church on Park Avenue.

Mr. Clements said the 2010 Supreme Court ruling essentially removed limits on what corporations and special interests can spend in politics, and said that since the decision, $40 billion in corporate money, often difficult to trace back to its source, has poured in. He said that in the 2016 presidential election alone, an estimated $3 billion to $5 billion was spent.

He said the ruling has contributed to a current state in politics where money truly does grant more rights to those who have it. Big donors who get politicians elected get much more attention and wield much more influence than ordinary citizens. He said only 0.5 percent of the U.S. population was responsible for that $40 billion.

"That's why we're under-represented," Mr. Clements said.

He said passing a 28th amendment - which would allow reasonable limits on political spending - would shift power back to citizens, and away from corporate interests.

Mr. Clements, who is also a constitutional lawyer, acknowledged it will be difficult to successfully get an amendment ratified - it needs approval of two-thirds of Congress and three-fourths of the states - but said he thinks it can be done. He said American Promise is a decentralized, grass-roots effort. He said more than half of U.S. senators and 150 U.S. representatives have expressed support for an amendment to reverse "Citizens United." Hundreds of cities and towns, and 18 states, have also approved resolutions supporting an amendment, Mr. Clements said.

An audience member asked why that number seems stuck where it is, and Mr. Clements said that currently, the support in Congress falls largely along party lines, with most Democrats in favor of the idea while most Republicans do not support it.

Still, Mr. Clements said that outside of partisan politics, polls consistently show an overwhelming majority of people support less money in politics. He talked about how support for an amendment at local and statewide levels would help build a groundswell that politicians wouldn't be able to ignore. He said American Promise later in the spring is launching a ballot initiative to get a question before voters in Massachusetts on the amendment for the November 2018 election.