Her opponent, Rep. Rick Berg (R-N.D.), has not yet released his fundraising numbers. He raised $950,000 last quarter and had $1.6 million in the bank as of May 23.
Heitkamp's new ad, her fifth of the cycle, attacks partisan gridlock in Washington.
"In Washington it's all just a game, one side against the other and good ideas like the Balanced Budget Amendment, or ending tax breaks for shipping jobs overseas, or tax incentives for creating jobs here get buried," Heitkamp says as preteen pee-wee players in red and blue jerseys charge toward a football. "I'm Heidi Heitkamp and I approve this message because we need a senator who will put partisanship aside and do what's right for our country."
Her campaign wouldn't say how much money is behind the ad, but said it was running statewide on broadcast television.
Heitkamp and Berg are locked in a tight race despite the state's Republican leanings — The Hill rates it a "toss-up."