The debate was feisty from the start with Ohio Governor John Kasich challenging political outsiders Donald Trump and Ben Carson for putting forward what he called “fantasy” proposals.

“Folks, we have got to wake up. We cannot elect somebody that does not know how to do the job. You have to pick somebody who has experience, somebody that has the know-how, the discipline,” Kasich said.

That brought a swift counterattack from Trump.

“He was so nice. He said, ‘Oh, I’m never going to attack.’ But then his poll numbers tanked and that is why he is on the end and he got nasty. He got nasty! So you know what, you can have him,” Trump said.

Former Florida Governor Jeb Bush clashed with Florida Senator Marco Rubio for missing Senate votes to campaign.

“But Marco, when you signed up for this, this was a six-year term, and you should be showing up to work. I mean, the Senate, what is it? Like a French work week? I mean, you get like three days where you have to show up. You can campaign or just resign and let someone else take the job,” Bush said.

“I don’t remember you ever complaining about John McCain’s vote record. The only reason why you are doing it now is because we are running for the same position and someone has convinced you that attacking me is going to help you,” Rubio replied.

Ben Carson, now leading in several polls, refused the opportunity to attack.

“I do, however, believe in [former President Ronald] Reagan’s 11th commandment [not to attack fellow Republicans] and will not be engaging in awful things about my compatriots here,” Carson said.

Former Arkansas governor Mike Huckabee declined an invitation to disparage Trump.

"When you look at him, do you see someone with the moral authority to unite the country?” asked moderator John Harwood.

“I love Donald Trump. He is a good man. I’m wearing a Trump tie tonight.  Get over that one, OK?” Huckabee said.

"Such a nasty question, but thank you, governor,” Trump added.

The candidates battled at times over their tax plans, government programs for retirees, job creation and the size of government.

But Senator Ted Cruz of Texas aimed his criticism at the questioners.

“This is not a cage match. And you look at the questions: Donald Trump, are you a comic book villain? ... How about talking about the substantive issues people care about?” Cruz asked.

The Republican contenders will have little time to rest. Their next debate is just two weeks away.