The American Action Network (AAN) is announcing a $100,000 ad buy today against DFL congressional candidate Rick Nolan, bringing to $780,000 the group's spending to help Republican incumbent Chip Cravaack in northern Minnesota. The ad, "Working Hard," echoes the Cravaack campaign in attacking Nolan for supporting congressional pay raises and missing votes during his tenure in the U.S. House back in the 1970s. The center-right "action tank" led by former Sen. Norm Coleman said it will run the ad on broadcast in the Duluth media market, accompanied by a paid digital advocacy campaign. This is AAN's fourth ad in the ever-tightening race for the seat held by Cravaack, who is holding a press conference this morning in the state Capitol. In a measure of national attention the contest in Minnesota's Eighth Congressional District has received, the Sunlight Foundation estimates more than $4 million has been spent by outside groups in the race so far.