The impeachment trial of Donald Trump is set to open on Thursday at noon, though the remainder of this week will likely be devoted to getting formalities and procedural requirements out of the way. The actual trial proceedings will get underway next week, following the holiday weekend.

But the outcome of the trial already appears determined. Under the requirements set out in the United States Constitution, to convict Trump — or any sitting president — and remove him from office requires a two-thirds majority, or 67 votes, in the Senate.

But according to a count by The Hill, a maximum of 10, and more likely no more than three, Republicans may even be considering the possibility of voting to convict Trump. If all 47 Democrats (including two independents) vote to convict, removal of Trump from office would require 20 Republican votes.

As such, on the surface, conviction seems unlikely barring an unprecedented break from party lines by a number of Senate Republicans.

Even without a vote to convict Trump in the impeachment trial, there are three other ways that Trump, at least in theory, could be removed from office.

The 25th Amendment

The assassination of 35th U.S. President John F. Kennedy (pictured) led to the passage of the 25th Amendment. Featured image credit: National Archive Getty Images

The 25th Amendment to the U.S. Constitution was passed by Congress in 1965 and ratified by the states in 1967. The amendment spells out how to transfer power in the event not only of a president’s death, but also if Congress or even the president’s own cabinet determines that he (or she) becomes incapable of carrying out the duties of his office — either due to a physical illness of some kind or a mental disability.

The 25th Amendment was a response to the assassination of President John F. Kennedy in 1963. After Kennedy’s death, there was confusion over how and when the transfer of presidential power to Vice President Lyndon B. Johnson should take place.

Given reports of Trump’s seemingly erratic behavior and public statements, the possibility of removing him using 25th Amendment provisions has been discussed on several occasions, not only in the news media and on social media. In 2018, even one senator, current presidential candidate Elizabeth Warren, called for the process of invoking the 25th Amendment to get Trump out of office.

The 25th Amendment has been invoked only four times, first in 1974 when the resignation of Richard Nixon handed the presidency to Vice President Gerald Ford. Ronald Reagan used the amendment’s provisions to temporarily hand power to Vice President George H.W. Bush during a 1985 surgical procedure. Bush’s own son, George W. Bush, also invoked the 25th Amendment twice, during routine medical procedures that required him to be placed under general anesthesia, in 2002 and 2007.

Resignation

37th President Richard Nixon remains the only one ever to resign the office. Featured image credit: Fox Photos Getty Images

Nixon, the 37th president, resigned the presidency on August 9, 1974, in the wake of the Watergate scandal. As The Christian Science Monitor recounts, just four days earlier the White House released a tape recording of Nixon in the Oval Office in which he instructed his Chief of Staff H.R. Haldeman to lie to the CIA, in order to quash the Watergate investigation.

The so-called “smoking gun” tape sealed Nixon’s fate, as the first piece of hard evidence tying him directly to the cover-up of crimes connected to the burglary of Democratic National Committee headquarters by White House operatives in 1972.

But even after the tape’s release, Nixon still remained in office — until a delegation of Republican senators led by Arizona’s Barry Goldwater visited him in the White House. Goldwater and the other senators told Nixon that after the “smoking gun,” he must resign or face removal from office by Senate impeachment trial.

Nixon remains the only president ever to voluntarily quit in the middle of a term. Whether Senate Republicans would urge Trump to resign appears extremely unlikely, however.

Death

Ninth U.S. President William Henry Harrison was also the first of eight presidents to die in office. Featured image credit: Hulton Archive Getty Images

While Trump’s removal by his own resignation, or by the 25th Amendment, appears far-fetched, it remains possible that he could be removed by the same force that ultimately removes us all — death. At age 73, and with limited public information about his health conditions, Trump’s life expectancy is unclear.

Of the 44 presidents prior to Trump, eight died while in office — almost 20 percent — according to The World Atlas. Of those eight, four — 50 percent — died as a result of assassination. Kennedy in 1963 remains the most recent president not only to be assassinated, but to die in office.

The first was the ninth president, William Henry Harrison, who was also the president who served the shortest period in office. Harrison died in 1841 of typhoid fever just 31 days, one month, into his first term.

Trump is reportedly an avid consumer of fast food, and in fact, an unhealthy diet was apparently the reason 12th President Zachary Taylor died in 1850. He is believed to have gobbled down a large amount of cherries, green apples, cold milk, and ice water on July 4, 1850. He quickly fell ill, and five days later, the president was dead from severe diarrhea.