"It was a really good night for Donald Trump. He could hardly have hoped for a better debate. You had a handful of rational moderates, [like] Congressman Delaney. Their soundbites are perfect and could replace half of the Trump ads next year because they come out and tell the truth. This stuff is crazy," said Gingrich, noting the far-left proposals from the candidates on immigration and health care.
"He really was, as somebody said, like the angry uncle who showed up at Thanksgiving and nobody wanted to set him off," he joked.
Gingrich said Sanders has at least been honest about raising middle-class taxes to pay for his version of "Medicare-for-all."
"The core of the Democratic Party is very, very left-wing and almost irrationally anti-Trump," he said, adding that they are not having a "rational debate" about taking away health insurance "from 180 million people."
He said he's interested to see how the primaries play out as moderate candidates try to push back against progressives.
"The challenge you have is among the most active Democrats, they are so polarized now that they say things that when you think about it, are totally irrational," he said.