Mainers Against Health Care Cuts is a left-of-center pro-Obamacare group. It is a project of the Sixteen Thirty Fund, a 501(c)(4) funding and fiscal sponsorship nonprofit created and managed by the Washington, D.C.-based consultancy Arabella Advisors.
Mainers Against Health Care Cuts is part of the Sixteen Thirty Fund, a network of liberal “dark money” groups across the country. Its focus is on opposing cuts to government spending on health care and opposing efforts to repeal and replace Obamacare. 
The Sixteen Thirty Fund established Mainers Against Health Care Cuts to target then-U.S. Rep. Bruce Poliquin, a Republican, in the 2018 election. The group ran ads attacking Poliquin for his vote to repeal Obamacare, and also for his vote in favor of the tax reform bill that eliminated Obamacare’s individual mandate to carry insurance. 
Separately, in 2017, the Sixteen Thirty Fund also provided hundreds of thousands to the Maine People’s Alliance, a left-progressive activist group, and Mainers for Health Care, a group supporting Medicaid expansion in the state. 
The Sixteen Thirty Fund was founded in 2008.  It operates alongside its charitable “sister” nonprofit New Venture Fund, which provides similar funding and fiscal sponsorship services to center-left organizations. Both groups, along with the Hopewell Fund and Windward Fund, are administered by Arabella Advisors, a philanthropy consulting firm based in Washington, D.C., that caters to left-leaning clients. 
The Sixteen Thirty Fund primarily targets vulnerable House Republicans by establishing political groups that sound local or state-based, as is the case in Maine and other states. In 2018, the Sixteen Thirty Fund was credited with providing a major boost for helping Democrats win a House majority. 
The left-leaning editorial board of the Washington Post criticized Arabella’s Sixteen Thirty Fund as a “big campaign donor” in a November 21, 2019, editorial that called on Congress to change nonprofit disclosure laws, noting in particular a $26.7 million anonymous donation to the Fund; the donation was later identified as having originated with New Venture Fund, another Arabella-network pass-through funding group. 
Mainers Against Health Care Cuts has also presented itself as a coalition of progressive groups that includes the Maine People’s Alliance, Mainers for Accountable Leadership, the Maine Small Business Coalition, and Organizing for America. The organization held a press conference in late 2017 announcing the release of new anti-Poliquin ads with these organizations. The ads accused Poliquin of trying to cut government funding for health care and trying to increase the cost of health care for senior citizens. 
Mainers Against Health Care Cuts teamed with the liberal group Not One Penny in 2018 to air numerous other attack ads against Poliquin, who ultimately lost that year despite winning a plurality of votes, because of the state’s ranked-choice voting system. One of the commercials attacked him for voting differently than Maine Republican Sen. Susan Collins, who voted against repealing Obamacare.