Giuliani's history raises legal questions as he takes on Trump defense

“The big problem here is how likely is he to become a witness in the case, whether it be in a grand jury or otherwise,” said Loyola Law School professor Laurie Levenson, a former federal prosecutor. “You can’t be a witness and a lawyer in the same case. That’s the big sticking point.”…

While Giuliani didn’t hold a formal position in the Trump presidential campaign, he often opened for Trump at rallies in the final months of the race, a role which would have had him in contact with top campaign operatives. He’s acknowledged he was in touch with FBI officials during the 2016 campaign and said the bureau’s rank-and-file were “boiling” over about the Clinton email investigation. Shortly before the FBI director at the time, James Comey, reopened that investigation that October, Giuliani said the Trump campaign had “a couple of things up our sleeves that should turn things around.”