WASHINGTON - A national conservative advocacy group founded by former U.S. Sen. Norm Coleman plans to flood Minnesota airwaves this fall to boost the chances of U.S. House Republican candidates.

The American Action Network said it is reserving $860,000 in airtime in Minnesota and Wisconsin this fall as part of a larger effort to establish a presence in the two states.

American Action's effort mirrors one already underway by the Democratic House Majority political action committee and the Service Employees International Union, which together plan to spend $890,000 in television ads in the weeks leading up to the election, focusing on U.S. Reps. Chip Cravaack and John Kline.

The ad reserves are part of an effort across the country to help Republicans in competitive races. In addition to the ads, American Action and its political action committee, the Congressional Leadership Fund, have already spent money to help Cravaack, funding direct mail, print ads and robo-calls that highlight his efforts to repeal the Affordable Care Act, as they are doing in 30 House races across the country. Cravaack is vying for a second term after unseating longtime Democrat Jim Oberstar.

But not all the money will go to ads and specific candidate efforts.

As part of its developing national grass-roots network, American Action will spend an estimated $10 million among select states to advocate on issues, register voters, recruit volunteers and buy office space, American Action spokesman Dan Conston said. The group also will help support existing organizations such as the Taxpayers League of Minnesota.

The large ad reserves come as Democrats ramp up their efforts to require nonprofit groups such as the American Action Network to reveal their donors.

Senate Republicans on Monday blocked consideration of a Democratic bill, the DISCLOSE Act, that would require nonprofits to name donors who contribute at least $10,000.

In the 2010, American Action spent more than $25 million on ads, with most of that money coming from undisclosed donors. During that election, the group ran ads in Minnesota supporting Cravaack's successful congressional campaign and U.S. Rep. Tim Walz's unsuccessful opponent.

Former U.S. Rep. Rick Nolan, the DFL-endorsed candidate running against Cravaack, said he expects to be targeted by Coleman's group this year in the general election.

"It won't be exclusively for us," he said. "But I'm sure I'm on the list."

First, however, Nolan has to get past an Aug. 14 primary against DFL challengers Tarryl Clark, a former state senator, and former Duluth City Council President Jeff Anderson.

Star Tribune staff writer Kevin Diaz contributed to this report. Corey Mitchell is a correspondent in the Star Tribune Washington Bureau. Twitter: @StribMitchell