Republican U.S. Sen. Scott Brown and his Democratic challenger Elizabeth Warren are set to square off for their third debate in Massachusetts' U.S. Senate race.
The debate takes place at Springfield Symphony Hall at 7 p.m. It's the only debate in the western part of the state.
The face-off comes a day after Brown received the endorsement of former Republican New Jersey Gov. Christine Todd Whitman and Warren met with construction workers at a Boston work site.
As the candidates gear up, outside groups are, too, hoping to affect the outcome of the high-profile race.
The groups say they're respecting a pledge signed by Brown and Warren, aimed at barring third-party organizations from buying television, radio and Internet ads.
Polls show the race, already the most expensive in state history, remains tight.
Copyright 2012 by The Associated Press