Republican presidential candidate Sen. Marco Rubio, R-Fla., center, answers a question as Sen. Ted Cruz, R-Texas, left, and former Florida Gov. Jeb Bush, right, listen during a Republican presidential primary debate, Thursday, Jan. 28, 2016, in Des Moines, Iowa.
Republican presidential candidate Sen. Marco Rubio, R-Fla., center, answers a question as Sen. Ted Cruz, R-Texas, left, and former Florida Gov. Jeb Bush, right, listen during a Republican presidential primary debate, Thursday, Jan. 28, 2016, in Des Moines, Iowa. Charlie Neibergall AP
Republican presidential candidate Sen. Marco Rubio, R-Fla., center, answers a question as Sen. Ted Cruz, R-Texas, left, and former Florida Gov. Jeb Bush, right, listen during a Republican presidential primary debate, Thursday, Jan. 28, 2016, in Des Moines, Iowa. Charlie Neibergall AP

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