The 25th Amendment: What happens if the president can’t work?

President Trump announced early Friday that he and first lady Melania Trump had tested positive for COVID-19. At 74 years old and obese, Mr. Trump is considered at higher risk for complications of the infection. On Friday evening, Mr. Trump was transferred to Walter Reed Medical Center “out of an abundance of caution,” where he will continue to do his job, the White House said.

White House spokesperson Kayleigh McEnany said Mr. Trump has mild symptoms but “remains in good spirits” and continued working throughout the day.

“Out of an abundance of caution, and at the recommendation of his physician and medical experts, the President will be working from the presidential offices at Walter Reed for the next few days,” McEnany said. “President Trump appreciates the outpouring of support for both he and the first lady.”

Still, the news of his positive coronavirus test drove an immediate surge in Google searches for the 25th Amendment to the U.S. Constitution, which lays out the succession for the executive branch should the president be incapacitated or deemed unable to carry out the duties of the presidency.

White House communications director Alyssa Farah said that despite the president’s stay at Walter Reed, he has not transferred power to Vice President Mike Pence.

“The president is in charge,” Farah said.

The 25th Amendment, which was ratified in 1967 following the death of President John F. Kennedy, includes a number of different provisions.

In Section 3, it outlines how the president can temporarily transfer his powers to the vice president and then resume the powers of office when he is ready. This has typically occurred when a president undergoes a medical procedure, as when George W. Bush underwent a colonoscopy in 2002 and 2007.

“I will undergo this morning a routine medical procedure requiring sedation,” Mr. Bush wrote in his 2002 letter to the speaker of the House and president pro tempore of the Senate, informing Congress that he was invoking the 25th Amendment. “In view of present circumstances, I have determined to transfer temporarily my Constitutional powers and duties to the Vice President during the brief period of the procedure and recovery.”

Once the procedure was completed, Mr. Bush took back the presidency from Vice President Dick Cheney.

Section 4, which has never been used, says that the vice president would become “acting president” if he or she, along with a majority of the president’s Cabinet, inform Congress that the president is “unable to discharge the powers and duties of his office.”

A president can challenge a Section 4 claim, if he disagrees, by informing Congress that he is fit to serve. The vice president and Cabinet majority would then have four days to make their case to Congress that the president cannot carry out the duties of the office, and lawmakers would have 21 days to decide whether to remove the president, which would require a two-thirds majority vote in both houses.

In addition, the 25th Amendment lays out what would happen if a president were to die in office or step down for any reason. “In case of the removal of the President from office or of his death or resignation, the Vice President shall become President,” it says in Section 1.

Section 2 addresses who would then replace the Vice President: “The President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress.”

There have been eight instances in U.S. history of presidents dying in office: William Henry Harrison, Zachary Taylor, Abraham Lincoln, James Garfield, William McKinley, Warren G. Harding, Franklin Delano Roosevelt, and John F. Kennedy.

Vice President Mike Pence is 61 and his office said that he tested negative for COVID-19 on Friday morning. The next two officials in the current line of succession for the presidency are octogenarians. House Speaker Nancy Pelosi, a Democrat, is 80 years old, and Senate President Pro Tempore Chuck Grassley, a Republican, is 87.

Fifty-six-year-old Secretary of State Mike Pompeo, who is fourth in line for the presidency, told reporters that he had tested negative for COVID-19 on Friday and had not interacted with Mr. Trump since September 15.