Fighting from behind in the polls, Brown was combative throughout the hour-long debate against Democratic Sen. Jacky Rosen.

Mr. Brown, who has never held elected office, has found himself outpaced by Senator Jacky Rosen, the low-key and well-financed Democratic incumbent. A debate Thursday night presents a key test.

Democratic incumbent Sen. Jacky Rosen will take the stage tonight in Las Vegas against GOP challenger Sam Brown in the only Nevada Senate debate. With less than three weeks until Election Day, it’s on