Heller's principle opponent for the nomination is Dawn Gibbons, a former three-term state assemblyman and the wife of current 2nd district Rep. Jim Gibbons, R-Nev., who has said he may run for governor in 2006.
Dawn Gibbons and Heller are the first candidates in a race the Reno (Nev.) Gazette-Journal said Thursday is likely to get more crowded.
"It's a coveted seat. We don't have many districts in this state," said Fred Lokken, political science professor at Truckee Meadows Community College. "It's an opportunity that doesn't come along often, so yes, there will be more."
Republican state Treasurer Brian Krolicki said he would decide soon whether he will join the battle for the 2nd or run for lieutenant governor since term limits prevent him from seeking re-election.
Lt. Gov. Lorraine Hunt of Las Vegas is running for governor in 2006. Republican Gov. Kenny Guinn cannot seek re-election because of term limits.
The congressional seat could be expensive, with campaign costs in a crowded field soaring above $1 million, according to some estimates.