MSNBC’s Brian Williams questioned Mark Halperin Thursday night on his “interestingly optimistic” take on Donald Trump’s chances, asking where he was getting information that led him to believe the GOP nominee had such a viable shot at the presidency.

Williams told the Bloomberg Politics co-managing editor, who critics say has taken a disproportionately pro-Trump outlook on the election, that he had been a reliable mainstream media ally of Trump’s.

“Mark Halperin, to you, I say this with charity in my heart as an every evening and weekly viewer,” Williams began. “When Donald Trump complains that he is not getting favorable coverage in the MSM, he has not been listening to you this cycle.”

“I think you’ve gone out of your way to find the path, argue for the path, forge the path for him, in an argumentative way with your co-host, to the nomination,” Williams continued. “Tonight I thought you were interestingly optimistic. Where are you getting the path of positivity you laid out on your broadcast tonight?”

Halperin, who appeared taken aback by Williams’ analysis of his own analyses, answered simply that it was “not a question of optimism.”

“It’s based on looking at the data and looking what’s going on in the battleground states,” Halperin said, before launching into a list of prerequisites necessary for Trump to take the lead.

“If there is a bit more of a national surge, and if it turns out his ceiling is higher than the Clinton folks think, if it turns out she doesn’t have the hold on the coalition of the ascendant that Barack Obama had, I think it’s possible he could find his way to 270,” he said.

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