What does it take to remove a president from office? A Monday night event sought to answer the question. 

Author David Priess, former CIA intelligence officer under Presidents Bill Clinton and George W. Bush, presented on his book "How to Get Rid of a President: History’s Guide to Removing Unpopular, Unable, or Unfit Chief Executives," laying out a historical roadmap for how a president could be removed from office. 

With special counsel Robert Mueller's probe on Russian interference in the 2016 election potentially nearing its conclusion, some Democrats have called for President Donald Trump's removal from office. 

“The title is intentionally provocative, but it does not mean, ‘how can we get rid of this president?’” Preiss said, who was also a former daily intelligence briefer for Mueller when he was FBI Director. 

He has explored a variety of options that can be used to remove a president but believes one has the most legitimate influence—simply waiting until the term ends to vote them out. 

No one can dispute the results of a fair election, he argued. 

However, Priess brought up two other methods—the 25th Amendment and impeachment. 

To invoke the 25th Amendment, which can be called upon if a president is "unable to discharge the powers and duties of his office," the Vice President and a majority of Cabinet secretaries must stand up to the commander in chief himself. 

Priess said this is unlikely to happen, though, and that the president has not displayed that he is incapable of making decisions on his own. To Priess, until Trump violates normal ethics or delves into insane behavior, such as “nominating a chicken to become a judge,” his inferiors cannot legally remove him.

“There’s no instance short of mass murder in which insubordination is appropriate or permissible," Priess said.

Deputy Attorney General Rod Rosenstein floated the possibility of invoking the 25th Amendment, according to a New York Times report

Sophomore Spencer Kaplan inquired about doctors examining the president’s mental state, but Priess dismissed the notion. 

“Mental health of officials is not something psychologists should assess," Preiss said.

However, Priess conceded that a rash, strange discussion by the president or signs of mental impairment should prompt a physician’s appointment.

For impeachment, only a simple majority is required in the House, which Democrats will control in the new session, so presumptive House Speaker Nancy Pelosi might have the votes to charge Trump with “high crimes and misdemeanors.” The Senate, however would require a two-thirds majority to impeach a president. 

Priess also mentioned a proximate example—President Richard Nixon’s resignation. Similarly, Republicans had not budged for months but completely flipped once the mounting evidence was too much. Priess predicted a similar scenario if Mueller's team piles up increasingly incriminating facts. 

“What was once unimaginable became inevitable, and it could happen again,” Priess said.