He said he didn't want to pursue a bill he knew wouldn't pass.
Trump brushed off Bush, saying he was trying to be a "tough guy."
He said he wants to repeal ObamaCare and have a plan based on "free enterprise."
"He has no idea what he is doing, and the country is going to hell,” said Trump.
Christie mocked Rubio's speaking style; Rubio responded by attacking Christie's character.
Christie hit Rubio for missing the vote on the Hezbollah Sanctions Act he claims as an accomplishment.
"When this transpired, I apologized to him then, and I do now."
Debate moderator said applause was too loud for candidates to hear their names being called.
Data provided by Google shows it as the top trending question for Bush.
Candidates are hoping to make a final impression just days before New Hampshire votes.