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.

Boston Fed president Susan Collins said the central bank will likely need to cut interest rates further, the latest in a chorus of Fed policymakers to publicly support more monetary policy easing after the first cut in more than four years.

GOP candidate Sam Brown spent Thursday’s Nevada Senate debate taking shots at Democratic Sen. Jacky Rosen, as he still faces a polling deficit with Election Day creeping nearer.