Former federal prosecutor warns CNN that Trump's actions are 'existential threat' to the FBI's integrity
Former federal prosecutor Samuel Buell talks with CNN (Screen cap).

Samuel Buell, a former federal prosecutor who now teaches at the Duke University School of Law, told CNN on Friday that President Donald Trump's actions attacking the federal law enforcement officials represent an "existential threat" to the integrity of the FBI.

When discussing the possibility that FBI Director Christopher Wray should resign if the Trump White House releases the controversial Nunes memo against his wishes, Buell said that he hoped Wray would stay on initially.

However, he warned that Trump's actions were putting Wray on a collision course and could very well force Wray to resign in the coming weeks.

"This goes to another level, this isn't ordinary procedure," he said of the memo's release. "He has to realize that we're at an existential point here with respect to the integrity of federal law enforcement."

Buell went on to lay down some markers for where Wray should draw the line and step down if Trump goes too far.

"He should not resign over the release of this memo," he said. "But if this memo is then used as a pretext to fire Rod Rosenstein and put in place someone who has the capacity to shut down Robert Mueller's investigation, then I think Christopher Wray has to consider resigning over that. Because that is an existential threat to the integrity of an FBI investigation."

Watch the video below.