A few days ago Speaker of the House Nancy Pelosi announced that she was pursuing legislation that would allow Congress to intervene in the invocation of the 25th Amendment. This, she said, was not about removing President Trump (the election is 22 days away at the time of writing) but about giving Congress greater oversight of the White House.
Regardless of the intention, let's talk about the 25th Amendment.
By the time the 25th Amendment was approved by Congress in 1965 and ratified by the states two years later, eight presidents had passed away while in office, starting with William Henry Harrison in 1841. John Tyler assumed the presidency among much consternation from Congress including his own party who referred to Tyler as "His Accidency," and his own cabinet called him "Vice President Acting President," which is just a devastating level of disrespect. Tyler's succession set the precedent for the Vice Presidents of Zachary Taylor (ate too much fruit and milk), Abraham Lincoln (assassinated), James Garfield (assassinated), William McKinley (assassinated), Warren G. Harding (stroke), Franklin D. Roosevelt (brain hemorrhage), and John F. Kennedy (assassinated).
But that line of succession didn't really cover what would happen if the President was alive, but incapacitated through illness or mental acuity, temporarily or permanently. James Garfield was in a coma for 80 days in 1881 before passing away from the effects of his assassin's bullet. Vice President Chester A. Arthur just sort of waited and tried to make it seem like he hadn't just stepped in as president. The line of succession also didn't account for what would happen if the President was unfit to serve but didn't want to relinquish power. That's what Congress started to debate in 1965.
The Presidential Succession Act of 1792 put the line of succession as such: Vice President - Senate president pro tempore (not the Senate Majority Leader) - Speaker of the House of Representatives. In 1886, five years after the assassination of James Garfield, Congress replaced the two congressional officials with cabinet officers, in the order of the date of creation of the individual agencies. No Senate President Pro Tempore had ever been president, members of Congress argued, but six Secretaries of State had been president.
The first real non-assassination/non-death Presidential succession crisis came in 1919 with Woodrow Wilson. 1919 came at the end of World War I but right in the middle of the global Spanish Flu pandemic (which started in Kansas). Wilson and his administration (and, to be fair/critical, so did most nations) straight up censored any talk of the flu epidemic that would end up killing between 50 and 100 million people worldwide. The 1918 Sedition Act basically made it illegal to criticize the government or the military, or say things to weaken the United States' position. Printing that x-number of soldiers were dying because of flu fell under that law. The censorship, both government-imposed and self-censorship, allowed the flu to spread more rapidly around the country and the rest of the world thanks to troop movements as well as countries at war not wanting to let their enemies know their weaknesses. Toxic masculinity, amirite? Historian/Author Carol R. Byerly:
[German General Erich] Ludendorff is famous for observing (flu outbreaks among soldiers) and saying, oh my God this is the end of the war. His soldiers are getting influenza and he doesn't want anybody to know, because then the French could attack him.
Anyway, I had taught for years that Woodrow Wilson died of a stroke. Verdict? MODERATELY TRUE. Wilson caught the Kansas Spanish Flu while negotiating the Treaty of Versailles in April 1919. His doctor told the press Wilson caught a cold from the spring rains in Paris. The Associated Press explicitly said it wasn't Spanish Flu. Wilson couldn't sit up, endured long bouts of violent coughing, and posted a 103-degree fever. Wilson was disoriented, certain that he was surrounded by French spies. Chief Usher Irwin Hoover:
We could but surmise that something queer was happening in his mind. One thing was certain: [Wilson] was never the same after this little spell of sickness.
In November 1919 he suffered a stroke that left him paralyzed on his left side and partially blind. One year later was the presidential election. Rather than capitulate to the growing growls in the Senate by the Obstructionists over Wilson's League of Nations (led by Henry Cabot Lodge) Wilson's wife, Edith, (and Dr. Cary Grayson) hid Wilson's debilitating condition from the press and other members of Congress. Why? In part because there wasn't any real clear guidance on what happens if the President is alive, but cannot actually do his job. So Edith Wilson essentially was President. Senator Albert Fall - who would go on to have his own issues to deal with - blasted the Edith Wilson presidency as "a petticoat government." Nevertheless, Edith Wilson ran the Wilson Administration until March 1921.
When the 20th Amendment was ratified in 1933, it did two things: (1) to move inauguration day from March 4 to January to avoid a couple of extra months of a lame duck presidency, and also to hammer down that the Vice President takes over in the event that the President cannot fulfill his duties. Furthermore, Congress will pick the President if the President and Vice President cannot fulfill their duties.
Politics are personal, and personalities can drive politicians to create new policies. For instance, when Franklin Roosevelt passed away in 1945, VP Harry Truman was having a bourbon in Speaker of the House Sam Rayburn's office when he found out he was now president. With no Vice President in place, Senate president pro tempore Kenneth McKellar became Presiding Officer of the Senate. (Side note: McKellar represented Tennessee in Congress from 1917 - the first directly-elected Senator from Tennessee - until he lost a bid for a 7th term to Al Gore, Sr.). McKellar and Truman weren't exactly buddies. Truman lobbied to make the Speaker of the House - his buddy Rayburn - next in line over McKellar. In 1947, it worked.
In 1955 President Dwight D. Eisenhower had a heart attack in Denver. Continued heart issues as well as a mild stroke drove Eisenhower to write a letter to Vice President Richard Nixon instructing him on what to do should Eisenhower become incapacitated, giving Nixon the power to determine if Eisenhower could not fulfill the duties of the office of the President. You can't have some James Garfield situation in the middle of the Cold War where no one knows who is really president. Driven by fears over the ongoing Cold War with the Soviet Union as well as Eisenhower's health issues, Congress started to formulate ideas to clear up the line of succession after a proposal from the American Bar Association was put before Congress. Senator Estes Kefauver (D-TN) took up the cause of this issue, but he himself died in August 1963 after suffering a heart attack on the Senate floor.
There were questions on November 22, 1963 as to whether or not Vice President Lyndon B. Johnson, riding two cars behind, was killed or injured in the assassination of President John F. Kennedy. Thanks to 170 years of shifting lines of succession, Congress had no real idea who would become president if both the president and vice president were unable, for whatever reason, to carry out the duties of the office. New York Times columnist James Reston:
Has the Congress prepared the presidency adequately for the possibilities of a violent age? Is the rule of presidential succession satisfactory for these days of human madness and scientific destruction?
Johnson had his own health issues, while Speaker of the House John McCormick was 71 years old and Senate president pro tempore Carl Hayden was 86. And so in January 1965 the Bayh-Cellar Resolutions in the House and Senate were brought forth recommending an amendment to the Constitution to clear the issue up. Congress debated points of both sweeping changes and semantics, focusing particularly on what was meant by an "inability" to carry out the duties of the office of the president, as well as wondering if they were creating a precedent where Congress could just decide to remove a sitting president. On July 6, 1965 the 25th Amendment was passed by Congress and sent to the states for ratification, which cleared the 75% mark in 1967.
There are four clauses to the 25th Amendment:
Section 1: If the president dies or resigns, the Vice President takes over.
Section 2: In the event that there is no Vice President (because he/she has ascended to the presidency), a majority vote in Congress appoints a Vice President.
Section 3: If the president tells the Senate president pro tempore and the Speaker of the House that he is unable to perform his presidential duties, the vice president become acting president until the original president notifies them in writing. The VP/acting president is not sworn in because the president keeps his designation and the right to return to office.
This was invoked in 1973 when Vice President Spiro Agnew resigned after a bribery scandal came to light. Nixon had joked that Agnew was his own impeachment defense, since no one would impeach Nixon if it meant that Agnew would become president. Agnew worked a plea deal with federal prosecutors in which he would plead no contest to federal charges in exchange for paying $160,000 in back taxes (thanks to a loan from Frank Sinatra) and a $10,000 fine. Agnew resigned, paving the way for Nixon to appoint - with Congressional approval - House Republican leader Gerald Ford as his new Vice President. Ford would invoke Section 3 nine months later when Nixon resigned over the Watergate scandal, and made Nelson Rockefeller his vice president.
Section 4 is where it gets sticky: The Vice President and a majority of "a body of Congress" can declare in writing to the Senate president pro tempore and the Speaker of the House that the president cannot perform the duties of the office, and the vice president immediately becomes acting president. The president, then, can offer a written declaration to the contrary and resume the office...unless within four days the VP and a majority body of Congress declares in writing again that the president cannot perform his duties, upon which Congress will vote on it. Back to the Congressional debates of 1965, Virginia Representative Richard Poff said Section 4 should be invoked when the president was simply "unable or unwilling to make any rational decision." The American Bar Association's John D. Feerick, who suggested the 25th Amendment, wrote that "unpopularity, incompetence, impeachable conduct, poor judgment, and laziness did not constitute an 'inability'" within the framework of the Amendment.
Section 4 has never been invoked, although the Reagan Administration came close on a couple of occasions. On March 30, 1981, less than three months after taking office, John Hinckley, Jr. shot President Reagan in an effort to - I kid you not - impress actress Jodie Foster. While Reagan was undergoing surgery, his administration prepared the paperwork to name VP George H.W. Bush president. The papers were never signed, against the advice of some members of Reagan's administration, members of Congress, and even Reagan's doctor. Stephen Knott, a professor of national security at the United States Naval War College, said that Reagan "came closer to dying than we were lead to believe at the time," and he thought the 25th Amendment should have been invoked in that instance, but they didn't "out of fear of upsetting the public, the markets, along with allies and adversaries."
Reagan White House Director of Communications David Gergen, on not signing the paperwork to invoke the 25th Amendment:
There is a very great reluctance to move on the Twenty-Fifth. Everyone is hesitant because in effect you are expressing less than full confidence in your chief executive. There is an overwhelming urge to convey a serene view to the world, and I think everybody in the room wanted to say, 'Hey, unless we are forced, we don't deal with that.
In 1987, as Reagan was dealing with the fallout from the Iran-Contra Affair, his staff complained that Reagan was acting "inattentive and inept" and raised the possibility of invoking Section 4 of the 25th Amendment. In Landslide: The Unmaking of the President, 1984-1988 journalists Jane Meyer and Doyle McManus reported from inside the White House:
[White House staff] told stories about how inattentive and inept the president was. He was lazy; he wasn't interested in the job. They said he wouldn't read the papers they gave him - even short position papers and documents. They said he wouldn't come over to work - all he wanted to do was to watch movies and television at the residence.
Reagan's new Chief of Staff - Howard Baker, Jr. - hadn't been on the job very long when he asked how the White House was running after Iran-Contra and got this report back. Baker began to observe Reagan's behavior to see if it lined up with what he heard. Baker disagreed with the remarks on Reagan, and didn't pursue Section 4 action.
The 25th Amendment exists to protect the democratically-elected president and, like the impeachment process, the difficulty of unseating a president is the point. But Congress' role in the 25th Amendment has been A Thing all the way back to 1792.