'Rudolph Giuliani is a walking argument for this impeachment': Constitutional law professor
Former U.S. Attorney Rudy Giuliani on Fox News (screengrab)

A constitutional law professor available on CNN in the wake of Monday's House Judiciary Committee hearings explained that the biggest argument for impeachment is former New York City Mayor Rudy Giuliani.

In a panel discussion, Brown University Professor Corey Lang Brettschneider explained that the president's lawyer would ultimately sink him.

"Look, Rudoph Giuliani is a walking argument for this impeachment," he said. "If you don't stop the president now, you don't bring these articles of impeachment about obstruction of justice, abuse of power; he will keep doing it. And Giuliani is showing that. He continues to go to the Ukraine and continues to lie about these fake conspiracy theories, and it's sort of walking argument for what happens when you leave power unchecked."

CNN's David Gregory explained that there is a "boldness" and "audacity," on the part of Rudy Giuliani, to continue to do whatever he and the president wants.

"Republicans know there's only so much they can defend some of this conspiracy theory plunging that Rudy Giuliani is doing," CNN's Abbey Phillips agreed. "It doesn't help them because it's paper-thin. It has been ripped apart numerous times in these hearings and public by Trump's own administration officials. People he appointed to their positions."

She explained that Giuliani was doing it because he thinks it's the direction the investigation is going, but that people in Congress don't want to be associated with shady characters connected to corruption in Ukraine.

"So, Trump is standing by him for now. He stands by people when he thinks they are being loyal," she continued. "The question is how long will that continue, especially when there is this parallel track in the Southern District of New York that is completely separate from all of this, and it is criminal."

Watch the panel discussion below: