Huckabee sparked outrage for invoking the Holocaust in his criticism of the deal.
“I think that the email scandal is going to be a devastating blow,” Trump said.
“Everyone is going to have an opportunity,” Priebus said. “I think it’s great.”
"Donald Trump, like every other candidate, will rise and fall,” said Santorum.
"I think most Americans don't want their tax dollars going to this," he said.
The GOP presidential candidate also criticized President Obama's record on the Middle East.
Christie said he is still deciding what to do with 11 million illegal immigrants in the U.S.
“I would be part of a coalition and I would take them down,” Kasich said.
“It's as serious, if not more serious a threat, than al Qaeda,” Lynch said.
The senator said the deal was made possible by changes in Iran's leadership.
“This deal paves Iran’s path to a nuclear arsenal,” he said.