Chris Hayes Mocks Newt Gingrich's Union-Leader Endorsement (VIDEO)

MSNBC host Chris Hayes took a skeptical look at the rise of Newt Gingrich on Sunday's "Up."

Hayes and his panel were reacting to the endorsement Gingrich received from the influential New Hampshire Union-Leader on Sunday. Hayes read a key quote from the endorsement -- "Newt Gingrich is by no means the perfect candidate" -- and sarcastically said, "call that 'ringing.'" He then joked that Mitt Romney would soon be running another out-of-context ad using the quote to attack Gingrich.

Other panelists were equally bemused by Gingrich's ascent to front-runner status. MSNBC's Ezra Klein called it "astonishing," and writer Michaela Angela Davis said the former House speaker was "dangerous."

Hayes also pointed out that, even though Gingrich has previously supported things like a cap-and-trade bill, and recently called for a more "humane" immigration policy, he has not been punished by the Republican base.

Hayes also dinged Bill Clinton for speaking to the conservative Newsmax magazine about Gingrich.

"Bill Clinton and your people ... next time you have the instinct to talk to Newsmax, call us up!" he said.