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Tucker Carlson challenged a former staffer on Hillary Clinton's presidential campaign to defend the legitimacy of Robert Mueller's probe into whether President Donald Trump colluded with Russia in 2016.

"Why lie about it and say we were never going to impeach him?" Carlson asked Joel Payne.

"That's not what's going on," Payne responded. "We're trying to find the truth as to what happened [in 2016]."

Payne said attacks on Mueller and his team may be continuing in order to "cover up their engagement with the Russian government."

He said the idea that Democrats are set on impeaching Trump as a side effect of the Mueller probe is overhyped.

Carlson said there has been no proof yet to show that Trump colluded with Russia.

Payne said former Trump campaign chairman Paul Manafort had questionable business dealings with foreign governments.

Carlson pointed out that most of those attributed to Manafort dealt with Ukraine and not Russia.

He and Payne however agreed that they found Manafort "shady" and as Carlson said, he would not even choose to have dinner with the longtime lobbyist.

Payne later said Trump and his team are continuing to run an "opposition campaign" against Mueller.

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