Rudy Giuliani is desperately trying to save Trump using 'the word of a KGB agent': CNN's David Gergen
Rudy Giuliani and Ukrainian politician Adriy Derkach

Trump attorney Rudy Giuliani this week has been in Ukraine working with a wide variety of shady characters with the intent of digging up dirt on former Vice President Joe Biden.

Among other people, Giuliani has been talking to are Andrii Telizhenko, a former Ukrainian diplomat who is also suspected of working for Russian intelligence operations, and Andriy Derkach, who attended the Dzerzhinsky Higher School of the KGB in Moscow and whose father was a former KGB officer.

CNN's David Gergen said that Giuliani's efforts to dig up dirt using sources with ties to Russian intelligence has already rendered whatever purported "findings" about Biden he discovers deeply tainted.

"I think what he is doing, working with the person he's working with over there, is so tainted that it poisons the whole effect of what he's trying to do," Gergen said. "I mean, to think the main point that's been reported, the main person he's been talking to, his father was head of intelligence for the KGB in Ukraine! The man himself graduated from a KGB school in Moscow! And the man himself was a member of... a pro-Russian party. Are we now going to have impeachment turn on the word of a KGB agent? Come on! Give me a break!"

Watch the video below.