In 1967, the 25th Amendment was added to the Constitution, meant to formalize a process for what happens if a president dies in office or becomes disabled — after more than a century of presidents suffering from life-threatening conditions and even undergoing secret surgeries. But the 25th Amendment is more complicated than it sounds.

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Before he agreed to become White House chief of staff in 1987, Howard Baker Jr. had a request for a longtime aide of his. Baker, a retired senator, asked James Cannon to assess the state of affairs inside the White House.

The presidency of Ronald Reagan was in “chaos,” Cannon wrote to Baker. Aides told him that Reagan was “inattentive and inept.” Cannon’s first recommendation, as reported in a 1988 book and confirmed by Cannon himself soon after, was shocking. “Consider the possibility that section four of the 25th Amendment might be applied,” wrote the aide, who had worked previously as a senior policy adviser to President Gerald Ford.

Diana Walker / Getty Images President Ronald Reagan

The 25th Amendment was added to the US Constitution in 1967. Compared to some amendments, it might seem a little obvious or procedural, but the 25th Amendment was the long-belated response to more than a century of crises, and some of America’s darkest and most chaotic moments, dealing with one simple question: What do we do if something is wrong with the president? The amendment has four parts. The first two codify what happens if the president or vice president dies or otherwise leaves office (the vice president becomes president, and the president can nominate a new vice president, respectively). The third outlines how the president can temporarily hand over power to the vice president. The fourth section — never used in the 50 years since it was adopted — gives the vice president and cabinet the power to declare that the president is “unable to discharge the powers and duties of his office.” It is heavily weighted in favor of the president’s ability to serve, enabling the president to force a congressional vote on the issue — a vote that would take two-thirds of both houses of Congress to keep the president out of power. In short, it’s a complicated and rigorous process that would require many elected and appointed officials to agree the president was unfit. But that, in 1987, was what Cannon suggested to Baker, as Jane Mayer and Doyle McManus reported in their 1988 book, Landslide: The Unmaking of the President. From the very origins of the United States, the country’s leaders did recognize that the question of presidential disability could be a problem, but they did little to work out how to resolve it. Presidential history is subsequently rife with stories of life-threatening conditions and even secret surgeries. Eight presidents have died while in office. Several have been shot. Many have suffered from serious illness — sometimes for months or, in at least one case, for more than a year — that clearly left them unable to run the country. Along the way, the country’s leaders allowed constitutionally questionable practices to become informal precedent, messed around with the order of presidential succession (one role the Constitution explicitly assigned to Congress), and blatantly hid those presidential illnesses from the public (and sometimes even the vice president and cabinet). Remarkably, it took the assassination of John F. Kennedy in 1963 — along with continued leadership from a former president, steady hands in Congress, and significant outside support — to finally address obvious issues from a constitutional perspective. Now, in 2017, many Donald Trump critics contend he is unfit for office, and some have held up the 25th Amendment as a way to get him out, returning its fourth section to the public discourse in the midst of a presidency that has raised many questions about little-known constitutional provisions. But that conversation has been speculative and focused on today’s political questions. A close examination of presidential history, however, reveals how exceptional and complex a move invoking the final part of the 25th Amendment would be, regardless of who’s president. It would be unprecedented. In fact, in looking at the nation’s history, something more fundamental emerges: No one has ever determined what, precisely, the Constitution means when it comes to disability. Tellingly, in 1987, James Cannon’s recommendation remained under consideration for a grand total of one day. He and Baker, two men with no constitutional role in the 25th Amendment process, and others observed Reagan in a meeting the next day and decided that he was not incapacitated, Mayer and McManus reported. The issue was not raised again.

National Archives Joint Resolution Proposing the Twenty-fifth Amendment to the United States Constitution.

The Constitution itself is notably light on the question of what happens if the president can no longer serve. During the convention, the framers spent far more of the summer of 1787 debating how the legislature would be apportioned and selected, the role and election of the president, and the treatment and future of slavery. But a delegate from Delaware raised a particular dilemma regarding the president.

“What is the extent of the term ‘disability’ & who is to be the judge of it?” asked John Dickinson, according to James Madison’s notes from the debates, of proposed language referencing a president unable to serve due to some inability. The question gets to the heart of the issue for a democratic republic with one person at the helm of its executive branch, and for a set of framers concerned with the concepts of tyranny, stability, and liberty: Who can — and should — have the power to declare that leader unfit? It’s a question those framers left untended. Instead, the limited, vague discussion of how the new nation would deal with a president serving less than a full term would be the only constitutional guidance, giving Congress authority to deal with presidential succession: In case of the removal of the president from office, or of his death, resignation or inability to discharge the powers and duties of the said office, the same shall devolve on the vice president, and the Congress may by law provide for the case of removal, death, resignation or inability, both of the president and vice president, declaring what officer shall then act as president, and such officer shall act accordingly until the disability be removed, or a president shall be elected. “Disability” remained undefined, and the question of who would determine it left unanswered. Within 20 years, it became clear that would be inadequate, as John Feerick, a lawyer and professor who played a key role in the development and passage of the 25th Amendment, details in his book The Twenty-fifth Amendment: Its Complete History and Applications. In 1813, Madison — now the president — postponed a meeting with senators indefinitely. His illness was serious, the vice president was old, and there was a vacancy in the next office in the line of succession — then the Senate president pro tempore. It turned out to be a false alarm: Madison recovered (and lived for more than 20 more years). The same could not be said for William Henry Harrison, who died on April 4, 1841 — a month after taking office as president.

Universal History Archive / Getty Images An illustration detailing the death of President William Henry Harrison.

His vice president, John Tyler, took the oath of office and asserted that, with Harrison’s death, he had become the president. Not everyone agreed Tyler was actually the president. Some argued that the Constitution’s language meant, as John Quincy Adams put it, that Tyler should continue to be addressed as the “Vice-President Acting as President.” It took two months for Congress to accede to Tyler’s position, recognizing him in a debated resolution as the president of the United States. In a classic example of a constitutionally questionable practice turning into informal precedent, the “Tyler Precedent,” as Feerick called it, would guide the way succession worked the next seven times a president died in office.

Bettmann / Bettmann Archive An illustration of President James A. Garfield being shot by Charles Guiteau on July 2, 1880.

What became clear 40 years later, in 1881, however, is that the death of a president can involve more than just who becomes president next. After Charles Guiteau shot President James A. Garfield on July 2, 1881, doctors first thought he would die because of his grave initial condition. He recovered just enough that doctors believed he might live. “The general feeling was expressed that the worst was over, and the nation began to take courage,” according to an extremely sympathetic, but extensive, account by Emma Elizabeth Brown in her 1888 book, The Life and Public Services of James A. Garfield, Twentieth President of the United States. In late July, Garfield had what Brown describes as a relapse that required surgery. Throughout August, Garfield declined. Who was serving as president, though? Garfield wasn’t exercising the “powers and duties” of his office. As presidential succession expert Ruth Silva detailed in a 1956 article, “During the eighty days of President Garfield’s fatal illness, he performed but one official act, the signing of an extradition paper.”

"The cabinet thought that the shock of taking any action on the matter might cause his death … the whole matter of succession and inability was dropped."

“Plans were suggested” for Vice President Chester Arthur to exercise the powers of the presidency while Garfield was sick, according to a report from the Congressional Research Service. But cabinet members ended up debating whether Arthur would become the president if he took over the duties during Garfield’s disability. Some cited Tyler’s actions after Harrison’s death, suggesting the same would apply here. What would happen, then, if Garfield recovered? Would he be unable to resume the presidency? “The cabinet thought that the shock of taking any action on the matter might cause his death,” Silva wrote of Garfield. “Consequently, the whole matter of succession and inability was dropped.” So the plans, according to the Congressional Research Service, never “progressed beyond the talking stage” — despite nearly three months in which the president of the United States couldn’t perform his duties. By September, Brown wrote that it was determined “the malarial atmosphere surrounding the White House was a constant drawback” to Garfield’s recovery and he should be moved. The president’s “last hope” — a trip to a cottage on the New Jersey shore — was planned. Workers literally put down new railroad tracks in New Jersey so the president’s train could go directly to the cottage. Attorney General Isaac Wayne MacVeagh, who was with the president at the cottage, sent a telegraph to the US minister to England on the evening of Sept. 12, describing in detail that the president had “eaten sufficient food with relish” and “[h]is wound and the incisions made by the surgeons all look better.” Garfield died a week later. Arthur became president. There was no vice president, no Senate president pro tempore, and no speaker of the House. There was, in short, no one authorized under the then-current succession law to act as president should something happen to Arthur. Despite Arthur’s expressed concern about those circumstances, that state continued until the Senate selected a president pro tempore nearly a month later, on Oct. 10, 1841. Congress did, though, eventually address this issue. In 1886, Congress changed the order of succession — removing the congressional leaders and replacing them with the members of the president’s cabinet, in the order the cabinet departments were created.

Department of the Navy, Naval Historical Center, Online Library of Selected Ships, Civilian Ships / Wikimedia The Oneida, an American steam yacht, photographed before World War I.

Perhaps the most complicated attempt to hide a presidential disability from the public was undertaken a few years later, in the summer of 1893. President Grover Cleveland arranged for a private yacht to take him out on the water so that he could receive secret surgery to remove a cancerous tumor from the roof of his mouth. The president, his friends and family, and doctors agreed to keep the diagnosis — and the surgery — a secret. The president would say he was taking a four-day fishing trip over the 4th of July holiday to his summer home in Massachusetts. (The surgery took place on a friend’s yacht, the Oneida.) People didn’t buy this, even at the time. A reporter asked one of the doctors involved, and he did not deny the surgery took place.

Photoquest / Getty Images Seated portrait of President Grover Cleveland.

As Matthew Algeo put it in his book that painstakingly details the cover-up, The President Is a Sick Man, “In the coming days, weeks, and months, Grover Cleveland’s closest friends, advisers, doctors, and even his pregnant wife would all dissemble to perpetuate the myth that the president was well. With their help, [Secretary of War Dan] Lamont would engineer a brazen and elaborate cover-up on behalf of a president whose reputation for honesty was unquestioned.” Lamont and the others claimed that Cleveland a) had an attack of rheumatism that led him to need some time to rest, and b) had “a bad case of dentistry,” because he had ignored necessary dental work, and so c) he decided to have the dentistry done on the yacht on the way to Massachusetts so he could be “cool and comfortable” while it was being done. Of course, none of that was true. But it wasn’t just the public that didn’t know. Vice President Adlai Stevenson didn’t know either. He had been at the World’s Fair in Chicago over the 4th of July holiday, but, as Algeo wrote, “he was determined to find out what was really going on.” After Stevenson told reporters he was headed to Massachusetts to “consult” with the president, Cleveland stopped him, instead sending him orders to “meet with Democratic Party leaders — on the West Coast.” Cleveland was not well, though. When Attorney General Richard Olney met with the president on July 8, he wrote that the president “did not talk much, was very depressed, and at that time acted, and I believe he felt, as if he did not expect to recover.” Olney went on to lie to reporters, however, telling them the president was “in good spirits, and apparently enjoying excellent health.” When a “suspicious-looking growth” was found near the wound in Cleveland’s mouth later in July, a second secret yacht surgery took place. The president again disappeared under the guise of a fishing trip. Ultimately, Cleveland did not leave to return to Washington until August 4 — with the vice president, most of the cabinet, Congress, and the American public still in the dark about the president’s cancer, surgery, slow recovery, and second surgery, and no one even entertaining the idea that someone else might need to be — or at least be acting as — president.

Fpg / Getty Images The coffin of President Warren G. Harding in the East Room of the White House, before his state funeral in August 1923.

Four presidents had serious health issues over the next half century. President Warren Harding became ill on a trip and was dead within a month; President William McKinley was shot and underwent surgery but died eight days later; and President Franklin D. Roosevelt died less than three months into his unprecedented fourth term. Of the president’s condition at his final inauguration in 1945, reporter John Gunther wrote, “I was terrified when I saw his face. I felt certain that he was going to die.” Roosevelt did die soon thereafter, from a cerebral hemorrhage.

Anthony Calvacca / Getty Images A soldier and two sailors reading newspapers announcing the death of President Franklin D. Roosevelt.

The fourth president at issue didn’t die in office — but his health issues had a more dramatic effect than the others on the way presidential disability was thought of in the years to come. In September 1919, Woodrow Wilson suffered a stroke that left his new wife, Edith, and his staff effectively running the country for more than a year. Silva, the succession expert, wrote in the 1956 article that “[t]here can be no question that Wilson was unable to perform his presidential duties much of the time from September 25, 1919 to March 3, 1921.” More than two dozen bills became law because the president took no action on them, the president did not meet with his cabinet for more than eight months, and “[t]here seems to be almost unanimous agreement that state papers were given to Mrs. Wilson first.” Government work came to a standstill if it could not be done without Wilson. The president’s central post-World War I foreign policy effort failed: The Senate defeated Wilson’s proposal for the United States to join the League of Nations.

Stock Montage / Getty Images President Wilson goes over papers at his desk as his wife, Edith Wilson, looks on.

But no action was ever taken to remedy the fact that the president was ill. In October 1919, Secretary of State Robert Lansing called a cabinet meeting; they discussed whether Vice President Thomas Marshall should become acting president — but, as Feerick details, White House aides pushed back and effectively stopped the discussion. Lansing, however, continued to hold cabinet meetings without the president. By February 1920, Wilson had fired Lansing. Even Congress considered action. The House Committee on the Judiciary held hearings in February and March 1920 into three bills and one resolution addressing the topics of presidential disability and removal from office. As in Garfield’s cabinet, however, lawmakers could not reconcile the issue of whether the president, once declared disabled, could resume his duties if and when that disability was removed. No significant steps were taken to address the issue in the years that followed, not even after the next president — Harding — died while in office. Congress tinkered with the succession act after FDR’s death in office, at the suggestion of then-President Harry S. Truman, reinserting the House speaker and the Senate president pro tempore into the line of succession ahead of the cabinet. The succession law, of course, did nothing to address presidential disability and who determines it — or the “acting president” debate.

Carl Iwasaki / Getty Images President Dwight Eisenhower smiles while wearing a shirt emblazoned with "MUCH BETTER THANKS" as he enjoys sitting on the hospital sun deck while recovering from a heart attack.

President Dwight D. Eisenhower, at two different points, took key steps that helped establish the need for what became the 25th Amendment. He suffered a series of illnesses that gave him keen insight into the Constitution’s inadequacies when it came to presidential succession and disability.

In September 1955, while on vacation in Colorado, the president had a heart attack. He did not walk again for more than a month, he did not leave the hospital for another two weeks, and, with the exception of the next few days after he was discharged, Eisenhower did not return full-time to Washington for another two months. In comments collected by Feerick in his earlier book, From Failing Hands: The Story of Presidential Succession, Eisenhower, his vice president, and senior White House staff were aware — and concerned about — how precarious the situation was, especially in those first days. The US government was no longer what it had been during Garfield’s illness, or even during Wilson’s presidency: WWII and the Cold War transformed the United States into a superpower, and at home, the New Deal era vastly expanded the importance of the federal government. Even still, during Eisenhower’s early recovery, the government operated, basically, by trusting cabinet members to do what they believed Eisenhower would have wanted and to bring questions to a cabinet meeting, at which the cabinet officers and senior White House staff decided what issues should be brought to the president.

The government operated, basically, by trusting cabinet members to do what they believed Eisenhower would have wanted.

Eisenhower acknowledged it wasn’t certain whether he would have been able to “act according to [his] own judgment” in the 48 hours after his heart attack. Vice President Richard Nixon and the president’s senior adviser, Sherman Adams, admitted that the “committee system,” as Nixon put it, could have been a disaster if a crisis had occurred. Everyone was “well aware that a national or international emergency could have arisen during the President’s illness to make this unofficial government by ‘community of understanding’ entirely inadequate,” Adams acknowledged. Eisenhower suffered two further illnesses over the next two years — an intestinal obstruction that required surgery and a stroke that temporarily impeded the president’s speech, leaving Nixon to attend a state dinner that night and a NATO meeting that took place nearly three weeks after the stroke. Both were serious matters that led Eisenhower to think seriously about the issue of presidential disability. Nixon noted that, after the surgery, Eisenhower “pointed out to me that for the two hours he was under anesthesia the country was without a Chief Executive, the armed forces without a Commander-in-Chief. In the event of a national emergency during those two hours, who would have had the undisputed authority to act for a completely disabled President?” Eisenhower, as a result, asked the Justice Department to consider the matter, and Feerick reports that the cabinet discussed the situation at a cabinet meeting on February 8, 1957. Although there was debate as to the best path forward, Feerick writes that “it was decided to push an inability amendment” to the Constitution. Both House and Senate leadership had issues with the proposal. It went nowhere. In the immediate aftermath of the stroke, Eisenhower’s growing frustration with his illnesses led him to tell his wife and doctor, as well as Adams, that he would leave office if he couldn’t carry out his duties. Adams took the comment seriously, advising Nixon, “You may be President in the next twenty-four hours.” Eisenhower quickly recovered, however. He did, though, put forth a change — albeit informal — that started the process moving when Congress wouldn’t do so. On March 3, 1958, Eisenhower’s White House made public his informal solution: a “letter agreement” between the president and vice president about how they would handle any presidential disability going forward. THE PRESIDENT and the Vice President have agreed that the following procedures are in accord with the purposes and provisions of Article 2, Section I, of the Constitution, dealing with Presidential inability. They believe that these procedures, which are intended to apply to themselves only, are in no sense outside or contrary to the Constitution but are consistent with its present provisions and implement its clear intent. (1) In the event of inability the President would--if possible--so inform the Vice President, and the Vice President would serve as Acting President, exercising the powers and duties of the Office until the inability had ended. (2) In the event of an inability which would prevent the President from so communicating with the Vice President, the Vice President, after such consultation as seems to him appropriate under the circumstances, would decide upon the devolution of the powers and duties of the Office and would serve as Acting President until the inability had ended. (3) The President, in either event, would determine when the inability had ended and at that time would resume the full exercise of the powers and duties of the Office. It was, effectively, a voluntary, informal version of what would become the 25th Amendment — a handshake agreement. It was, though, only an agreement — subject to change, potentially at a time when such a change could cause a national crisis.

National Archives / Getty Images President Lyndon B. Johnson takes the oath of office as president after the assassination of President John F. Kennedy on November 22, 1963.

In the aftermath of Eisenhower’s three illnesses, congressional leaders and outside legal experts appeared agreed that change was necessary. The American Bar Association underwent an effort beginning in 1960 to devise a solution to the inadequacies of the constitutional scheme. The Senate Judiciary Committee’s Subcommittee on Constitutional Amendments held hearings in June 1963 on legislation relating to presidential inability.

In the meantime, the “handshake agreement” would have to do. Attorney General Robert F. Kennedy wrote to his brother, President John F. Kennedy, in an August 1961 opinion that he had “conclude[d] that the [Eisenhower-Nixon] understanding of March 3, 1958, is in keeping with the Constitution, and that the precedent set by it could appropriately be followed by this Administration.” In an article detailing what happened next, Feerick wrote, “After years of unsuccessful attempts to agree on a proposed solution to the problems of presidential inability and vice-presidential vacancy, the United States Congress was finally jolted into action by the assassination of President Kennedy.” Feerick knew; he served as the chair of an American Bar Association Committee on Presidential Inability and Vice Presidential Vacancy in 1964. In early March 1964, former President Eisenhower weighed in on the matter, recommending a constitutional amendment to Sen. Birch Bayh, who was taking the lead on the issue in the Senate, and detailing his thoughts on the proper way to address both presidential succession and presidential disability issues. He later appeared at an ABA conference on the issue in May of that year, leading the New York Times to proclaim, “EISENHOWER BACKS DISABILITY CHANGE.” The widespread agreement that this would need to be addressed, however, also ushered in a series of debates about how it should be addressed. Sen. Kenneth Keating of New York — who served on the constitutional amendments subcommittee alongside Bayh — supported there being two vice presidents (the “seeming novelty” would eventually wear into “acceptance,” he believed) and believed Congress should be left the power to legislate “on inability procedures.” Bayh, who chaired the subcommittee, did not give in to either of those requests, but he did accept a handful of others — including a key one that kept the order of succession in the hands of Congress and out of the Constitution, as Bayh had wanted to do. In 1965, the proposal moved through the Senate with only minor changes from the previous Congress. On Jan. 28, 1965, President Lyndon Johnson issued a lengthy statement in which he said, “I most strongly endorse the objective of both [Senate- and House-proposed amendment resolutions].” Once both chambers had passed the resolutions, however, a conference committee had to work out three differences — all relating to the timeline for the process of addressing disputes over claims of presidential disability. The four parts of the amendment proposal were, with those exceptions, set: The vice president would “become” president in the case of the death, removal, or resignation of the president. The president — with approval from both chambers of Congress — could name a new vice president in the event of a vacancy. The final two portions would address presidential inability, providing that the president — or vice president, with agreement from the cabinet — could alert the House and Senate leaders to a presidential disability, making the vice president the acting president until the president informs the congressional leaders that the disability no longer exists. The amendment would also provide for a vote of Congress should the president disagree with the vice president and cabinet on the status of the claimed disability. By July 1965, compromises were reached, the differences ironed out, the chambers had voted, and the proposed amendment was sent to the states for ratification. On Feb. 10, 1967, the final necessary states ratified what was then declared officially the 25th Amendment at a formal White House ceremony later that month.

Bettmann / Bettmann Archive Gerald R. Ford is sworn in as the 40th vice president in ceremonies in the House chamber on Dec. 6, 1973.

The 25th Amendment, of course, was quickly put to use. After more than 150 years of the country proceeding through administration after administration without a vice president for at least part of the term, President Richard Nixon was able to nominate Gerald Ford to take over the vice presidency after Spiro Agnew resigned on Oct. 10, 1973. Ford was nominated two days later, and he became vice president by December after the Senate, then the House, voted to confirm his nomination.

Ford would be vice president for less than a year. Nixon resigned from office in the midst of Watergate investigations and, for the first time in US history, a man who had not been elected to national office took the presidency. With the Tyler precedent now clear constitutional law, Ford nominated his own vice president. Vice President Nelson Rockefeller served out the rest of the term after being confirmed by both chambers of Congress. Neither the president nor vice president were elected — a reality only made possible by the 25th Amendment.

Neither the president nor vice president were elected — a reality only made possible by the 25th Amendment.

When John Hinckley Jr. shot at President Ronald Reagan in 1981 — just 70 days into the new administration — there was no question that the president was unable to discharge the powers and duties of his office for at least a period of time. It was the type of situation Eisenhower had been through, been uncomfortable with, and pressed for a constitutional amendment to address. As Feerick wrote, “By most accounts, as the President underwent surgery, the events at the White House were characterized by a lack of coordination.” Despite that, the White House — including Vice President George H.W. Bush — took no action to invoke the 25th Amendment, despite a situation that seemingly called for a temporary transfer of authority. Four years later, Reagan’s doctors found a potentially cancerous growth during another procedure and wanted to remove it the next day. Although it appeared to be the perfect, short-term invocation of the 25th Amendment that Eisenhower had alluded to when expressing his concern about the time he was under anesthesia, the White House took confusing actions in this regard. The president, as dictated by the amendment, sent a letter to the House speaker and Senate president pro tempore alerting them to the fact that he would be temporarily turning over the powers and duties of the presidency to his vice president, George H.W. Bush — but the letter also claimed that he was not doing so under section 3 of the 25th Amendment. Despite that, as countenanced by the amendment, Reagan also sent a letter prepared before his surgery to the congressional leaders once he was out of surgery and ready to resume his powers and duties.

Historical / Getty Images President Ronald Reagan views a giant get-well card while recuperating at George Washington Hospital from a gunshot wound suffered in an assassination attempt by John Hinckley, Jr.

Privately, though, the president, first lady Nancy Reagan, and the president’s chief of staff, Donald Regan, all described the actions in their private notes as being an invocation of the 25th Amendment. The vagueness of the Reagan years surrounding how actually to implement the 25th Amendment led to a Commission on Presidential Disability, which issued a series of recommendations in January 1988 for how future administrations should address presidential disability — including advising new presidents to “discuss the amendment and devise plans of action for all medical contingencies.” Once in office, President George H.W. Bush quickly held a meeting to discuss presidential disability. Ten days later, on April 28, 1989, White House press secretary Marlin Fitzwater described the agreed-upon plans to the media — informing the public, as well. The practice continued — like the Eisenhower-Nixon “letter agreement” before the 25th Amendment — forward into the Clinton, George W. Bush, and Obama administrations. In 2002, President George W. Bush did directly invoke section 3 of the amendment, turning power over to Vice President Dick Cheney for a little more than two hours while the president received anesthesia during a colonoscopy; he did so again, for similar reasons, in 2007. The Trump White House did not provide any comment about whether the president and vice president, or the president and any senior staff, have discussed the treatment of the presidential disability sections of the 25th Amendment.