Republican U.S presidential candidate and New Jersey Governor Chris Christie reacts during the second round of the GOP debate.
Two candidates who formerly participated in the main stage debates - New Jersey Gov. Chris Christie (R) and former Arkansas Gov. Mike Huckabee (R) - will join former Sen. Rick Santorum (R-Pennsylvania) and Louisiana Gov. Bobby Jindal (R), who have participated in the previous three early debates.
Christie and Huckabee both failed to register high enough in the polls to qualify for the main-stage debate.
The debate will notably exclude former New York Gov. George Pataki (R) and Sen. Lindsey Graham (R), who failed to garner the 1% support among likely Republican voters in several select polls needed to qualify.
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