FARMINGTON HILLS, Mich. — Aides say Mitt Romney is out and Rick Santorum is doubtful for a March 1 presidential debate in Atlanta sponsored by CNN.
Romney's campaign said Thursday that the former Massachusetts governor has participated in 20 debates and was unable to schedule the Georgia forum. Santorum's campaign said the former Pennsylvania senator also is unlikely to attend.
It was unclear if the debate would go forward with only Newt Gingrich and Ron Paul, assuming they agree to attend.
CNN scheduled the debate a few days before what's known as Super Tuesday, when 10 states hold primaries and caucuses on March 6.
All four Republican candidates are scheduled to debate Feb. 22 in Mesa, Arizona.
Arizona and Michigan hold primaries on Feb. 28.