The GOP presidential candidates on Thursday all refused to back Donald TrumpDonald John TrumpTillerson: Russia already looking to interfere in 2018 midterms Dems pick up deep-red legislative seat in Missouri Speier on Trump's desire for military parade: 'We have a Napoleon in the making' MORE's call to ban Muslim immigration, one of the more controversial stances he has taken during his campaign. 

Trump stood by his call when moderators at the Fox Business Network debate asked him if he wanted to rethink his position. He added that many of his Muslim friends have called him to express support for his policy.

"We have to stop with political correctness. We have to get down to creating a country that doesn't have the kind of problems that we've had with people flying planes into the World Trade Center, with the shootings in California," Trump said, noting that his ban would only be temporary.

"We can't be the stupid country anymore." 

Jeb Bush immediately pushed back and asked Trump to reconsider.

"This policy is a policy that is impossible to build the coalition necessary to take out ISIS," he said, referring to the Islamic State in Iraq and Syria. 

"The other Arab countries have a role to play in this."

The Bush team has repeatedly hit Trump on this issue, with Bush calling Trump "unhinged" last year. But moderator Neil Cavuto turned to Bush, asking him whether those who agree with Trump are also "unhinged."

"No, not at all. I can see why people are angry and scared, because this president has created a condition where our national security has weakened dramatically. I totally get that," he said.

Then the other candidates joined in. 

John Kasich and Chris Christie reiterated calls to not admit Syrian refugees; Ted CruzRafael (Ted) Edward CruzSasse statement: Trump nominee who spread conspiracy theories has a ‘tinfoil hat’ Coalition of 44 groups calls for passage of drug pricing bill For the sake of our democracy, politicians must stop bickering MORE touted his call to suspend the resettlement of refugees in the U.S. from any country where Islamic terrorism is active; And Ben Carson called for a group of experts to study new immigration guidelines. 

Marco RubioMarco Antonio RubioTrump must send Russia powerful message through tougher actions McCain, Coons immigration bill sparks Trump backlash Taking a strong stance to protect election integrity MORE didn't directly address the question, though he has declined to back it before, instead calling to strengthen refugee vetting policies and bashing President Obama for underestimating ISIS.