PORTLAND — A group linked to Democratic mega-donors has given half a million dollars to a union-backed organization hoping to influence this year’s state elections, according to state campaign finance reports filed this month.

The reports show that the Democracy Alliance’s State Victory Fund LLC contributed $500,000 to Rebuild Maine, a group founded by Maine’s largest unions and the Maine People’s Alliance.

Democracy Alliance spokeswoman Elizabeth Bartolomeo said the limited liability company is “dedicated to funding efforts in states that will help expand and engage voters about issues they care about and inspire participation in our democracy.” She didn’t respond to follow-up questions about where the State Victory Fund gets its money.

Democrats nationally are trying to gain back political power by capitalizing on a backlash to Republican President Donald Trump’s presidency, while Republicans are defending seats they’ve won in recent years in states like Maine. The Democracy Alliance hopes to elect Democrats in key states; its network of progressive donors have long included former MaineToday Media owner S. Donald Sussman.

The donation in Maine comes as voters prepare to elect a new governor to replace term-limited GOP Gov. Paul LePage. Parties are fighting over control of the state Senate, which Republicans control by one seat, and the 151-seat House, where Democrats have 74 seats and Republicans have 70 alongside six independents and one Green Independent Party lawmaker.

The Democratic National Committee’s legislative arm has reported contributing $520,000 to Maine Democratic groups since last December, while state campaign finance reports do not show contributions this year from such national Republican groups.

The Maine Republican Party reports raising just short of $175,000 this year, compared with just over $800,000 reported in contributions for the Maine Democratic Party. About one-third of the Maine GOP’s money comes directly from commercial sources, while much of the state Democratic Party’s money comes from other political groups.

Republican gubernatorial nominee and businessman Shawn Moody, Democratic gubernatorial nominee and Attorney General Janet Mills and independent State Treasurer and publicly financed candidate Terry Hayes report they’ve raised roughly $1 million apiece through mid-July. Meanwhile, economic development consultant Alan Caron, an independent, is largely self-financed and reported raising over half a million dollars.

About half of Moody’s $1 million comes from the candidate himself, who owns a chain of auto collision repair stores. Another roughly $150,000 has come from commercial sources like automobile and roofing companies, while individuals have contributed about $380,000.

Meanwhile, 95 percent of Mills’ donations come from individuals. With a $206,000 campaign war chest, she has about $112,000 less cash going into the November races than Moody.

A fight is also heating up over a ballot question to raise taxes to establish universal home care for seniors and people with disabilities. The pro-home care effort has received $100,000 from Service Employees International Union on top of $350,000 from a nonprofit bankrolled by billionaire George Soros.

Meanwhile, Maine banking, real estate, hospital and business groups have teamed up to raise shy of $90,000 to oppose the ballot question.

A new state law requires major donors who give over $100,000 to ballot referendum campaigns to disclose the top five sources of their funds. But that law won’t be in effect until 90 days after lawmakers adjourn their ongoing special session.