A new poll from a respected online survey research company indicates that Sen. Susan Collins’ once-strong approval rating in Maine has plummeted in recent months.

The poll by Morning Consult, which was conducted online with nearly 2,000 Maine voters between April and June, found Collins had the second-lowest approval rating of any U.S. senator, besting only Mitch McConnell, the Senate majority leader from Kentucky. Meanwhile, Maine’s other senator, Angus King, an independent who caucuses with Democrats, was ranked as the most liked senator in the nation.

Collins’ approval rating dropped 16 points from the first quarter of 2019, the most of any senator in the survey.

The Morning Consult poll numbers for Collins, which show that 45 percent approved of her while 48 percent disapproved, prompted an onslaught of crowing by Collins’ opponents.

“This new polling reflects the fact that we can’t count on Sen. Collins to be an independent advocate, she has chosen her party and special interests in Washington over the people of Maine,” Maine Democratic Party Chairwoman Kathleen Marra said in a prepared statement Thursday. “She turned her back on all but the wealthy for a tax bill that rewarded corporations while threatening health care for everybody else. Mainers are fed up and ready for change.”

Collins’ campaign spokesman, Kevin Kelley, said they were not surprised by the new numbers, as “Collins continues to be subjected to a nonstop barrage of negative and false attacks fueled by millions of dollars in dark money.”

“But as soon as Mainers focus on next year’s campaign and Sen. Collins’ extraordinary record of bipartisan accomplishments, we are confident that she will prevail just as she has in past elections when extreme, out-of-state interests have tried to defeat her,” Kelley said.

The new polling numbers come just a day after another national political action committee, NextGen America, announced it would spend $1 million in Maine trying to unseat Collins. The PAC focuses on turning out young voters in support of liberal or progressive candidates and causes.

The PAC plans to organize students on 11 different college campuses in Maine over the next year with the focus on defeating Collins. Collins’ seat is one of several being targeted by national groups in hopes that Democrats can recapture the majority in the upper chamber of Congress.

Another PAC, Main Voters, has reported spending $15,000 so far for online anti-Collins ads. The independent expenditure group is running a “Stop Collins” campaign that calls Maine’s senior senator a “right-wing radical” who talks “like a moderate.”

Main Voters reports receiving much of its funding – $100,000 – from former MaineToday Media owner, financier and philanthropist S. Donald Sussman, according to Federal Election Commission records.

Collins has faced increasing scrutiny in her home state since her vote to confirm U.S. Supreme Court Justice Brett Kavanaugh last fall. She also has taken heat for her vote in favor of a tax bill that cut federal income tax rates, with critics complaining the cuts largely went to the country’s wealthiest people and corporations.

Despite the declining poll numbers and increasing attacks, Collins’ campaign has been able to collect record amounts of cash – announcing this week that it had raised $6.45 million and was sitting on a campaign war chest of $5.4 million.

At least four Democrats have signed up to be their party’s nominee in the 2020 race against Collins. Leading that pack is Sara Gideon, a Freeport Democrat and the speaker of the Maine House. Gideon’s campaign collected just over $1 million in the 10 days after she announced she would seek the party’s nomination next June.

Other Democrats in the race include longtime lobbyist and activist Betsy Sweet, attorney Bre Kidman and retired Air Force Maj. Gen. Jonathan Treacy.

Another group, Maine Momentum, organized as a nonprofit social welfare organization, also is targeting Collins in its 16 Counties Coalition campaign. As a nonprofit, the group does not have to disclose its funding sources.

The organization is headed by former staffers for Gideon and Rep. Chellie Pingree, who represents Maine’s 1st District, and says it wants to educate Mainers about Collins’ record, including her votes to pass Trump’s tax cuts and end the individual mandate under former President Obama’s signature health care law.

Organizers said that campaign will hold Collins “accountable” on tax cuts and health care policy without telling anyone how to vote.

Former Gideon spokesman Chris Glynn, now spokesman for the 16 Counties Coalition, said the tax cuts ended up benefiting “really large corporations and wealthy special interests.”