The 25th Amendment formally outlines the transition of power if the president is unable or unfit to serve.

Section IV allows the vice president and a majority of the Cabinet to remove the president from office.

Americans have been particularly interested in the amendment since President Donald Trump took office.

Yet another report indicates that President Donald Trump's top-most advisers have discussed using the Constitution to remove him from office.

In September 2018, an anonymous senior official in the Trump administration wrote an op-ed in The New York Times, claiming there's a "quiet resistance" undermining the president.

The official wrote that "there were early whispers within the cabinet of invoking the 25th Amendment."

Later that month, The New York Times, citing anonymous officials who were briefed on the meetings, reported that deputy attorney general Rod Rosenstein discussed invoking it in conversations with other Justice Department officials after Trump fired James Comey as FBI director in May 2017.

And on Thursday, CBS revealed that former FBI deputy director Andrew McCabe told "60 Minutes" that he and other Justice Department officials met to discuss whether they could get a majority of Cabinet members to remove Trump from office after Comey's firing. Trump fired McCabe in March 2018.

Trump himself reportedly didn't know what the 25th Amendment did. When former adviser Steve Bannon told him early in his term that it posed the biggest threat to his presidency, according to Vanity Fair, Trump said, "What's that?"

Read more: A senior member of the Trump administration says they are part of a secret resistance working against the president in the White House

After President John F. Kennedy was assassinated, Congress proposed and the states ratified the 25th Amendment in 1967 to formally outline the transition of power. Before that, the vice president didn't officially have the power to take over.

The amendment states that if the president dies, resigns, or is removed from office, the vice president becomes president. If there is a vacancy in the vice presidency for any reason, the president can choose someone to fill it.

And if the president is unable to fulfill his duties — like when President George W. Bush was under general anesthesia for colonoscopies in 2002 and 2007 — he can temporarily transfer his powers to the vice president, and get them back when he's done.

But Section IV is what some liberals have been frantically searching for more information on, because it could be a way to legally remove Trump from office.

A legal loophole to legally remove the president

President Donald Trump with members of his Cabinet: Treasury Secretary Steven Mnuchin, Commerce Secretary Wilbur Ross, US Trade Representative Robert Lighthizer and White House National Trade Council Director Peter Navarro. Chip Somodevilla/Getty Images

Under the amendment's fourth stipulation, it would only take 14 people to depose the president — Vice President Mike Pence and 13 of Trump's 24 Cabinet members.

Section IV reads:

"Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President."

John D. Feerick, former dean of Fordham Law School, is one of the chief architects of the 25th Amendment who shepherded it through Congress in the early 1960s.

He told Business Insider in March 2017 that the senators who signed the provision into law specified that declaring the president unfit must rely on "reliable facts regarding the president's physical or mental faculties," not personal prejudice.

"If you read the debates, it's also clear that policy and political differences are not included, unpopularity is not included, poor judgment, incompetence, laziness, or impeachable conduct — none of that, you'll find in the debates in the congressional record, is intended to be covered by Section IV," Feerick said.

Policy and political differences, unpopularity, poor judgment, incompetence, laziness, or impeachable conduct — none of that is intended to be covered by section IV.

Section IV goes on to say that if two-thirds of both houses of Congress don't vote to uphold the decision and keep the vice president in charge within 21 days, then the powers and duties automatically transfer back to the president. So if the president doesn't want to give up his office, Feerick explained, he doesn't have to if Congress agrees he shouldn't.

Akhil Reed Amar, a leading constitutional scholar at Yale University, said in a podcast for the National Constitution Center on the topic that the president's own running mate is the one who triggers a "palace coup," in order to maintain political stability.

"Here's the key point: The vice president is the pivot in the whole process," Amar said. "Unless the vice president puts himself — maybe one day, herself — forward, no one else can really basically, at least within the 25th Amendment framework, proclaim an unwilling president 'disabled.'"

The idea is that the Cabinet and VP are the president's closest advisers, Feerick said, so they would be the ones with the best sense of his mental faculties. They, and Congress, could also consult doctors to evaluate the president's physical and mental health in order to determine if he or she is fit for the job, though they don't have to.

The 25th Amendment is a separate process from impeachment, which allows Congress to remove a sitting president if a majority of the House of Representatives votes that he has committed treason, bribery, or other high crimes and misdemeanors, and a trial in the Senate convicts him.

In either case, legal scholars argue, the goal is to make the process as objective as possible.

"In a time like this of unusual crisis, one had to count on leaders in the executive branch and Congress to really be patriots, not partisans," Joel K. Goldstein, a constitutional expert at St. Louis University, said at a symposium that Fordham Law School hosted in September.

A renewed interest in the 25th Amendment since Trump took office

The last five years of Google Search data for "25th Amendment." Google Trends

Americans have been brushing up on their knowledge of the Constitution during Trump's presidency, according to Google Trends data.

The search term "25th Amendment" spiked in popularity after Trump took office, particularly after he signed the controversial travel bans, and after he tweeted an edited video of him body slamming CNN.

The two highest data points for Google searches were after the senior official wrote the anonymous op-ed in The Times, and after former Republican Sen. Bob Corker of Tennessee responded to a tweetstorm Trump went on about him in October 2017. "It's a shame the White House has become an adult day care center," Corker tweeted. "Someone obviously missed their shift this morning."

Interest was also rejuvenated amid the release of the explosive book, "Fire and Fury" — whose author, Michael Wolff, said the amendment was brought up "all the time" in the White House.

Feerick, who didn't discuss applying Section IV to Trump, said he hopes this renewed interest in the Constitution will encourage Congress to consider filling some of the legal gaps in the amendment that he and other legal scholars have proposed over the years.

For example, the Constitution doesn't outline what happens if the vice president is unable to serve, and he and other experts agree that the order of succession shouldn't include members of Congress as it does today.

"It's important that people be educated about the Constitution. It's our greatest charter of liberty," Feerick said. "I'm really happy that there's greater education going on — I'm obviously not happy about all the division in the country — but I'm happy that at least there's greater education being provided about the amendment."