HOUSTON -

"Who's telling the truth?" was the central issue in a much-anticipated debate between Lt. Gov. David Dewhurst and state Sen. Dan Patrick, candidates in the May 27 runoff for the Republican nomination for lieutenant governor.

And neither Dewhurst nor Patrick, who entered the debate favored to unseat Dewhurst, gave any ground during the one-hour debate aired statewide Friday night from Houston.

Both professed opposition to immigration law changes, federal health care programs, same-sex marriage and other issues. They differed on who is telling the truth about the other.

Dewhurst, lieutenant governor since 2003, lost by 13 percentage points in March's GOP primary to fellow Houstonian Patrick, a radio talk show host and tea party favorite.

The winner faces Democratic state Sen. Leticia Van de Putte of San Antonio.