AUGUSTA — Another outside political group is spending six figures on television ads in Maine, this time supporting incumbent Republican Sen. Susan Collins as she faces what could be her toughest reelection battle.

A financial disclosure report filed Monday with the Federal Election Commission shows that a group called 1820 PAC spent $276,780 on “media placement” in support of Collins. That is roughly one-third of the money that 1820 PAC – presumably named for the year Maine attained statehood – has collected from a handful of wealthy donors around the country, with $500,000 alone coming from New York billionaire Stephen Schwarzman.

1820 PAC is just the latest in a likely blizzard of outside or independent groups – many funded with “dark money” from unnamed donors – as well as out-of-state donors, who will try to sway Maine voters headed into the 2020 elections. Federal law prohibits independent groups from coordinating with candidates. But 1820 PAC’s entire website is devoted to supporting Collins – who has yet to officially announce her reelection bid – and a 30-second ad posted on YouTube talks about her bipartisan ratings and work on issues important to the elderly, veterans and Maine’s defense industry.

“Susan Collins: Effective. Independent. In the Maine tradition,” says the ad, which uses stock footage of Collins made available by her office several months ago.

The six-figure, pro-Collins media blitz comes at a time when opponents of Collins are seizing on a new sexual misconduct allegation against Supreme Court Justice Brett Kavanaugh to remind Maine voters about her pivotal vote to support his nomination. The vote prompted several progressive groups to raise more than $4 million for an as-yet-undetermined Democratic opponent in 2020. But Collins also experienced a massive surge in donations to her would-be campaign after the Kavanaugh vote.

Collins’ opponents are trying to chip away at her reputation as a moderate Republican by tying her to President Trump – who is unpopular with independents and moderates who have supported her in the past – and to Republican Senate Majority Leader Mitch McConnell.

“At the time of his confirmation, there was plenty of evidence that put into question Brett Kavanaugh’s fitness for the Supreme Court,” Maine House Speaker Sara Gideon, a Democrat who is running for Collins’ seat, said in a tweet on Tuesday. “Senator Collins cast a critical vote to confirm him anyway, and she said she doesn’t regret it. It’s time for a senator who puts Mainers first.”

Collins’ supporters and Republicans have been highly critical of Gideon’s out-of-state fundraising – even as Collins courts non-Maine donors as well – and of several other organizations that have not disclosed their donors. One of those “dark money” organizations, the 16 Counties Coalition, was set up as a nonprofit to pressure Collins on issues important to moderates and is staffed by several longtime Democratic operatives, including a recent spokesman for Gideon.

A spokesman for the Maine Democratic Party, in turn, seized on 1820 PAC’s spending as a suggestion that Collins’ supporters are worried.

“We’re 14 months out from election day and the 22-year senior senator’s numbers have cratered so much that six-figure positive ads are coming out to prop her up,” party spokesman Alex Stack said.

Collins’ campaign spokesman, Kevin Kelley, pointed to an AARP poll over the summer showing the senator leading Gideon by 17 percentage points in a head-to-head matchup, although several independents are also hoping to be on the November ballot.

“A dark money group operated by Sara Gideon’s former staffer has already spent more than $1 million attacking Senator Collins’ record, and yet they refuse to tell anyone who is funding them,” Kelley said. “What are they hiding?”

Spending on Maine’s Senate race is widely expected to set new records for the state. Five people have filed paperwork with the FEC to seek the Democratic nomination: Gideon of Freeport, progressive advocate and lobbyist Betsy Sweet of Hallowell, attorney Bre Kidman of Saco, retired Air Force major general Jonathan “Tracer” Treacy of Oxford and Michael Bunker of Bangor.

1820 PAC formed in March and lists a Washington, D.C., post office box as its address, which is common for political action committees and super PACs. The treasurer of the organization, Thomas Datwyler, did not respond to a request for comment on Tuesday.

Financial reports filed by the PAC show that seven individuals or entities donated $776,000 to 1820 PAC.

The largest donor, by far, was Schwarzman, a close Trump ally who serves as CEO and co-founder of the private equity firm Blackstone Group. The campaign finance watchdog group, the Center for Public Integrity, said the $12.9 million donated by Schwarzman and his wife, Christine, during the 2018 election cycle ranked him ninth overall among individual political donors. All of that money flowed to Republican or conservative candidates and organizations.

Schwarzman’s Blackstone Group also owns one of the health care organizations that has bankrolled a national ad campaign seeking to pressure members of Congress, including Collins, on legislation dealing with unexpected medical bills. The political action group Doctor Patient Unity reportedly reserved more than six-figures worth of airtime in Maine – part of a national ad campaign that The New York Times recently pegged at $28 million – for ads that tell listeners to “ask Senator Collins to protect patients.”

Blackstone Group owns TeamHealth, an organization that owns physician practices and helps staff emergency rooms. The company and another private equity-backed physicians’ practice group is fighting to defeat legislation that aims to end so-called “surprise billing,” which is when patients receive unexpected invoices from doctors or ER facilities that do not participate in their insurance coverage, The New York Times reported.