BOSTON -- U.S. Sen. Ed Markey and Congresswoman-elect Ayanna Pressley, both Massachusetts Democrats, on Friday rallied in support of a state ballot question that would create a commission to advocate for overturning the Citizens United Supreme Court decision.

Citizens United was a 2010 decision that allowed corporations and labor unions to raise and spend unlimited amounts of money on political activity as long as they do not coordinate directly with a candidate's campaign. Overturning the court ruling, and letting Congress limit corporate contributions, would require a constitutional amendment.

"We want the green grassroots to determine who wins elections, not the amount of green-backed dollars which you can bring into the process," Markey said at a press conference outside Boston City Hall.

Pressley said the goal is to give everyone an equal voice in politics. "Everyone deserves to be heard and to have a seat at the table of democracy, and this is how we ensure that we do not create a hierarchy of voice," Pressley said.

U.S. Sen. Elizabeth Warren, D-Massachusetts, has also endorsed the ballot question.

The ballot question, Question 2 in the Nov. 6 election, would create a Citizens Commission in Massachusetts to research, report and make recommendations to assist in drafting and promoting a constitutional amendment. If the effort is successful, the group pushing the ballot question -- American Promise -- hopes to conduct similar initiatives nationwide.

Pressley, who defeated U.S. Rep. Michael Capuano in the Democratic primary and is unopposed in November, pledged that she will not accept campaign contributions from corporate PACs.

Pressley said she "cannot in good conscience" take money from pharmaceutical companies during an epidemic of opioid addiction or from the gun lobby given ongoing gun violence.

Markey, asked after the event, would not make a similar pledge. "I'm focused now on this issue of getting all of the big undisclosed money out," he said.

Asked if he would distinguish between corporate and union money, Markey said his ultimate goal is full public financing of all campaigns.

Pressley left the event before the question about union money was asked, but said in a statement afterward, "Labor unions have a long history of fighting for the rights of workers; corporations do not. I am proud of the union support we have received and look forward to continuing to work with them on issues like health care, immigration, and education."

Supporters of the ballot question say overturning Citizens United is a way to stop special interests from having a larger voice in politics than working class citizens. "Campaign finance reform is the core issue of our time," said Ian Kea of MassVote. "The root of the problem is special interests being able to influence and buy our elected representatives."

Markey said, "Yes on 2 begins the process of taking the power away from those huge corporate barons and giving it back to the people in our country."

Markey pointed to federal tax reform as one example where he said special interests led to the passage of corporate tax breaks.

Paul Craney, a spokesman for the Massachusetts Fiscal Alliance, which is opposing the ballot question, said he believes the efforts of the commission would be unconstitutional. "It's acknowledging that individuals have rights but stripping everyone else of rights, which includes corporations and unions," Craney said. "To put in the U.S. Constitution that only individual people have rights and every other entity doesn't is laughable."

Craney said the ballot question would empower political officials - who would appoint the commission members - to "come up with ways to regulate public speech."

"That's why you have the Constitution's First Amendment, we don't believe government is the best judge," he said.

The Massachusetts Fiscal Alliance has not formed a ballot committee to oppose the question. Craney said that it is because the group is not raising or spending money, just doing public interviews.