Democrats aren't waiting for freshman Republican U.S. Rep. Tom Cotton to announce whether he plans to challenge U.S. Sen. Mark Pryor next year.
Two political action committees said Thursday they plan to spend $270,000 on a television ad that attacks Cotton.
A Pryor campaign spokesman says he'd heard an ad may start running but wouldn't comment about it.
The groups Patriot Majority USA and Senate Majority PAC use the ad to criticize Cotton for seeking a national spotlight.
A spokesman for the groups says the ads will start running Thursday night in the Little Rock and southern Arkansas media markets.
A Cotton spokeswoman didn't immediately return a voice mail seeking comment.
Cotton hasn't said whether he'll seek re-election to the House or challenge Pryor, the state's only congressional Democrat.