US Senator Marco Rubio, whose surprisingly strong showing in the Iowa caucuses made him the new target of his Republican rivals in the presidential race, faced strong attacks for his lack of experience during a debate Saturday.
After finishing a respectable third in Iowa on Monday, Rubio hopes to carry that momentum to New Hampshire, the next state to hold intra-party voting in the long process of choosing the next president of the United States.
The candidates faced a broad range of questions during the nationally televised debate, which proved to be a chance for the governors among the seven candidates on the stage to shine at the expense of two current senators and two political outsiders.
The 44-year-old Rubio, serving his first in the US Senate, faced some of the toughest verbal assaults.
Asked about the assertion that he is "not ready to be president of the United States," he said he was proud of his record in the Senate, including "bringing accountability" to the US agency for war veterans and supporting sanctions against terrorist groups.
New Jersey Governor Chris Christie, who has been warning voters against voting for another first-term senator as Americans did with Barack Obama in 2008, said the Rubio's record was weak and accused him of being absent from the Senate when critical votes were held.
"You have not been involved in a consequential decision where you had to be held accountable," Christie said. "You just simply haven't."
He said Rubio, the son of immigrants from Cuba, was "a smart person and a good guy, but he simply does not have the experience to be president of the United States."
The candidates also were asked about North Korea's launch of a ballistic missile only an hour before the debate began.
Front-runner Donald Trump said he would "let China solve that problem. They can do it quickly and surgically."
Former Florida Governor Jeb Bush said North Korea had been emboldened by the "strategic patience of the Obama administration" that has allowed countries like North Korea to "fill the void" left by the US.
"The next president of the United States is going to have to get the United States back in the game, and if a preemptive strike is necessary to keep us safe, then we should do it."
Trump also decried the murders of Christian hostages by Islamic State and defended his vow to use torture to extract information from potential terrorists.
"I would bring back waterboarding, and I’d bring it back a hell of a lot worse than waterboarding," he said.
Trump, who leads the polls in New Hampshire, returned to the debate stage after boycotting the last debate just days before the Iowa caucuses. New Hampshire voters will go to the polls Tuesday.
The field of candidates shrank to eight since three candidates - US Senator Rand Paul of Kentucky, former US senator Rick Santorum of Pennsylvania and former Arkansas Governor Mike Huckabee - dropped out after poor showings in Iowa.
Trump, a billionaire businessman from New York, finished second in Iowa behind US Senator Ted Cruz of Texas.
Also participating in the debate were Ohio Governor John Kasich and retired neurosurgeon Ben Carson.
The only candidate still actively running who was not invited to participate in Saturday's debate was Carly Fiorina.
Fiorina, a former executive at technology company Hewlett-Packard, criticized the network hosting the debate for excluding her in a video released by her campaign.
The results of the New Hampshire primary are expected to determine whether more of the Republican candidates drop out.