"It's typical of the Obama administration," the GOP presidential candidate said.
The ads will run in Iowa and New Hampshire, two early voting states.
Trump's campaign called Sam Nunberg a low-level, part-time consultant.
“It doesn’t get us closer to beating Hillary Clinton,” Priebus said.
Huckabee sparked outrage for invoking the Holocaust in his criticism of the deal.
Carson also discussed illegal immigration in an NBC interview.
“I think that the email scandal is going to be a devastating blow,” Trump said.
Priebus said it's not unreasonable to say that Republican candidates ought to support GOP.
“Everyone is going to have an opportunity,” Priebus said. “I think it’s great.”
Sanders said he was surprised by Clinton's reluctance to state a position on Keystone XL.