More than $1 million has poured into state House and Senate campaigns this year from national campaign organizations set up by the Democratic and Republican parties.

The money aims to sway voters heading to the polls Nov. 8 and, with luck, seize control of Maine’s Legislature, especially the upper house that has shifted back and forth between the two parties in recent elections.

Most of the cash, nearly $900,000 through the end of September, came from the Democratic Legislative Campaign Committee, whose largest donor is Wal-Mart and its employees.

Its counterpart on the other side of the political divide, the Republican State Leadership Committee, said it has chipped in $205,000 for Maine races so far.

State Rep. Barry Hobbins, a Saco Democrat who is a board member of the Democratic Legislative Campaign Committee, said the group has been “very helpful” in assisting his party’s candidates in Maine, especially in recapturing the Senate in 2012 after the GOP “ran the table” two years earlier to seize it.

He hopes Democrats do as well this time around as his party tries once again to reverse the 20-15 Republican advantage in the state Senate.

Hobbins said Maine is an especially attractive place to spend campaign money because the dollars go a long way. It’s cheaper than most states to buy advertising in print, radio and television, he said.

Hobbins, who said he worked quietly but effectively to bring the campaign cash to his home state, said it’s important to hold state legislatures that serve as a first step toward national offices and control the congressional redistricting process that occurs every 10 years.

“State legislatures continue to be a proving ground, pitting liberal candidates advocating for higher taxes and bigger government against those running to lower taxes, increase economic opportunity and preserve individual rights,” said Adam Temple of the Republican State Leadership Committee.

He said that’s why his organization “has been so deeply involved in states such as Maine where we’re committed to keeping the Senate majority and are devoting resources to help make that happen.”

The Democratic Legislative Campaign Committee, formed in 1994, aims “to build and maintain winning, state-of-the-art campaign committees in all 50 states by providing campaign services through a continuing partnership with legislative leaders, professional staff, and supporters.” It focuses its efforts on legislative races “where we can impact Democratic majority status in the current election cycle.”

The Republican group, formed in 2002, is still racing to catch up to its Democratic counterpart in terms of funding and impact.

Funding for both is murky. Their contributors are not regularly disclosed with anywhere near the detail required of candidates.

But the Center for Responsive Politics says that an Internal Revenue Service report in May lays out some of the biggest donors to the Democratic organization.

Its top giver? Wal-Mart.

Counting all of the donations from companies, their employees and their workers’ families, Wal-Mart-related contributions to the Democratic Legislative Campaign Committee totaled $253,500.

Others donating more than $100,000 to the group were the American Federation of State, County and Municipal Employees, the National Education Association, Astellas Pharma USA, Rai Services, the Nuclear Energy Institute, the Pharmaceutical Research and Manufacturers of America, Eli Lilly & Co., Genentech and PACs for Teamsters, painters, firefighters and electrical workers.

Hobbins said big companies and labor unions donate most of the money. He said the business interests also give to the Republicans “to hedge their bets.”

Both the Republican State Leadership Committee and the Democratic Legislative Campaign Committee are IRS-designated 527 nonprofit organizations specifically established to influence elections, an outgrowth of a Supreme Court decision in 1976 that barred the government from restricting political speech by limiting how much people can spend to get their point of view out to the electorate as long as they don’t actively coordinate their efforts with specific candidates.

Democratic Legislative Campaign Committee donations in Maine this year:

July 29 – $50,000 to the Maine House Democratic Campaign Committee

July 29 – $50,000 to the Maine Senate Democratic Campaign Committee

Aug. 5 – $50,000 to the Maine House Democratic Campaign Committee

Aug. 5 – $50,000 to the Maine Senate Democratic Campaign Committee

Aug. 5 – $50,000 to the Maine Democratic State Committee

Aug. 19 – $50,000 to the Maine House Democratic Campaign Committee

Sept. 9 – $100,000 to the Maine Democratic State Committee

Sept. 13 – $50,000 to the Maine House Democratic Campaign Committee

Sept. 13 – $50,000 to the Maine Senate Democratic Campaign Committee

Sept. 16 – $150,000 to the Maine Democratic State Committee

Sept. 23 – $100,000 to the Maine House Democratic Campaign Committee

Sept. 23 – $131,000 to the Senate Democratic Campaign Committee