Former Gov. Tommy Thompson and businessman and political novice Eric Hovde were locked in a tight race for the Republican Senate nomination in Wisconsin primary Tuesday night.

With 30 percent of the vote counted, Thompson was leading Hovde by 33.8 to 31 percent, Politico reported.

Former Rep. Mark Neumann, backed by grassroots conservatives and the Tea Party Express group, was third with 22.5 percent and state Assembly Speaker Jeff Fitzgerald had 12.7 percent.

The winner will face of Rep. Tammy Baldwin of Madison, who was unopposed for the Democratic nomination and would become the first openly gay U.S. senator in history. the candidates are seeking the seat of retiring Democratic Sen. Herb Kohl.