In this May 5, 2018, file photo, Speaker of the House Sara Gideon, D Freeport, speaks to reporters in her office at the State House, in Augusta, Maine. Gideon is driving home her attack on GOP Sen. Susan Collins for accepting corporate donations. Credit: Robert F. Bukaty | AP

Democrat Sara Gideon is swearing off campaign donations from corporate political action committees and backing efforts to disclose secret donors in an effort to curb the influence of special interests in Washington — and pressure GOP Sen. Susan Collins for taking money from corporate PACs.

In a new policy paper, Gideon’s campaign outlined several positions she said would blunt corporate power in policy making. In addition to refusing donations from corporate PACs, Gideon says she backs legislation that would require disclosure of dark money donors and supports efforts to overturn the Supreme Court’s Citizens United decision that allowed unlimited corporate and union spending in federal elections. She also said she’d refuse meals and gifts from lobbyists, and travel funded by special interests. The Collins campaign accused the Democrat of hypocrisy.

Gideon wants to make the power of big money a central theme of the Senate race, a contest that’s expected expensive political race in Maine history. National Democrats are vowing to pour millions of dollars into the effort to unseat Collins, a popular centrist who’s considered vulnerable after backing key parts of Trump’s agenda. Collins, meanwhile, already has raised the most money of any candidate in state history.

In announcing her goals, Gideon said, “The era of special interests blocking progress on every issue from access to health care to the cost of prescription drugs to tackling climate change has to end.”

Accusing Gideon of paying lip service, the Collins campaign noted that she’s already accepted corporate donations funneled through Democratic Senate leader Chuck Schumer’s PAC. And Gideon’s state-level PAC previously received money directly from corporations and corporate PACs.

“The hypocrisy is stunning. Sara Gideon is trying to have it both ways. As speaker of the Maine House, she built her career on corporate money. More than three quarters of her leadership PAC was funded directly by corporations and their PACs ranging from pharmaceutical companies to the insurance industry,” said Kevin Kelley, a campaign spokesman.

Collins already had the most money ever raised by a Maine candidate — $8.6 million in the last reporting period — and spending by the candidates and outside interests is expected to reach upward of $80 million to $100 million by Election Day.

Gideon, who is backed by the Democratic Senatorial Campaign Committee, is facing activist Betsy Sweet, attorney Bre Kidman, former Google executive Ross LaJeunesse and travel agent Michael Bunker in the Democratic primary. Also in the race are several independents and a Green Independent.

Kidman criticized Gideon’s efforts to get money out of politics as “paying lip service to a hot topic while obscuring the larger issue” of corporate PAC money being “laundered” through other PACs.

“The idea that a candidate can take corporate PAC money in this way and still claim to be serving the interests of getting money out of politics only makes a confusing issue more confusing for the average voter,” she said.

Collins’ campaign for a fifth term could be her most difficult race yet. The 67-year-old is viewed as freshly vulnerable in a state where a tradition of political independence is clashing with rising polarization and partisanship.

Democrats have targeted Collins for her votes for Supreme Court Justice Brett Kavanaugh and the GOP tax cut. They’ve accused Collins of failing to do enough to stand up to President Donald Trump, who’s facing an impeachment trial in the Senate.

It’s becoming common for Democrats running for federal office forgo donations from corporate PACs in a gesture aimed at targeting corporate influence. But corporate PACs generally account for a fraction of fundraising, and Gideon’s campaign noted that she’ll continue to accept from corporate executives and leaders, just not PACs.

And her pledge not to accept gifts and meals applies only to registered lobbyists, not necessarily their employers, who also wield influence.

The issue could resonate with some Maine voters, but Gideon will have to be sure it doesn’t backfire because opponents will be combing through her fundraising reports for any missteps, said Mark Brewer, political science professor at the University of Maine.

“There’s a risk that if you make that kind of a claim: You have to make sure you don’t get tripped up on it,” he said.