Ronald Reagan
Although Eisenhower wrote a letter to Nixon instructing him what to do in the event of him not being able to carry out his presidential duties, it wasn’t legally binding and certainly not invoking the 25th Amendment of the Constitution. That would happen for the first time on July 13, 1985, when Ronald Reagan would use the Amendment that deals with issues related to presidential succession and disability.
He would relinquish his duties to his then vice president George H.W. Bush while he underwent surgery at Bethesda Naval Hospital to remove cancerous polyps from his colon. However, this may have been the first time a president has used the 25th Amendment but it would certainly be the shortest.
After admission to the hospital, and being administered general anesthesia, Bush would take over as acting president. The surgery lasted just under three hours and was successful. It would only be a total of eight hours later that Reagan was out of commission before he would notify the Senate that he was fit and able to resume his duties as president of the United States.
George W. Bush
Although the 25th Amendment was only invoked for the first time in 1985, it would be used again, twice during 2002 and 2007. It would be another Bush on the end of another surgical procedure (procedures) that required the administrating of anesthesia.
This time it would be the son of Reagan’s former VP, George W. Bush. On June 29, 2002, then president Bush would invoked Section 3 of the 25th Amendment just before going under or a colonoscopy, making his VP Dick Cheney the acting president.
The exact same thing would happen for a second colonoscopy in 2007, and the exact same VP would briefly take the reigns of power.