Famed civil liberties lawyer and professor Alan Dershowitz weighed in on the controversy over the impartiality or bias of special counsel Robert Mueller and his investigation into Russian election interference and alleged collusion with the Trump campaign.

Here's video of Dershowitz talking about Mueller:

.@AlanDersh on Robert Mueller: "I think he's a zealous prosecutor and if he were going after @HillaryClinton, he'd be going after her with as much zeal. Now that's not true for some of the people on his staff." @TeamCavutopic.twitter.com/Dc9gmNMZj9

— Fox News (@FoxNews) December 29, 2017

Dershowitz says Mueller is trustworthy, but...

Dershowitz said that it was a bad idea to leave the investigation to Congress because it's too partisan, but defended Mueller's credibility as a non-partisan prosecutor of the law.

"I don't think he's partisan, I don't think he cares whether the Democrats or the Republicans benefit from this," Dershowitz said on Fox News. "I think he's a zealous prosecutor and if he were going after Hillary Clinton, he'd be going after her with as much zeal. Now that's not true for some of the people on his staff."

"He should never have allowed these people to serve on this investigative staff, if they had the points of view that they've had towards Hillary Clinton and towards Donald Trump," he added.

"That was a mistake," he continued, "when you're going after a president or a presidential candidate, you have to be 'Caesar's wife,' you have to be above reproach, and he didn't do a good enough job in vetting the people that he brought on to the prosecution and the investigative team, and that hurts his credibility."

Collusion is not a crime

Dershowitz also reiterated his opinion that even if Trump or members of his administration were found to collude with the Russians, it would not be a crime per se.

.@AlanDersh on Russia probe: "Before something can be a crime you have to find a provision in the federal criminal code that makes it a crime." @TeamCavutohttps://t.co/vgDUpMaL0cpic.twitter.com/qiw8u6Nepr

— Fox News (@FoxNews) December 29, 2017

He admits that it would be very damaging politically, even if colluding with the Russians would not be itself criminal.

"If the president and his campaign say to the Russians, 'look if you help me get elected, we'll help you with sanctions,' that would be terrible politically but it simply wouldn't be a crime," he explained.