Seven Republican presidential contenders will take part in a live debate tonight. It will air from 5 to 7 Pacific Daylight Time on CNN and again from 8 to 10. Scheduled to participate are: Rep. Michele Bachmann; businessman and talk show host Herman Cain; former House Speaker Newt Gingrich; Rep. Ron Paul; former Minnesota Gov. Tim Pawlenty; former Massachusetts Gov. Mitt Romney; and former Sen. Rick Santorum.