Acting President of the United States underwent colon cancer surgery while under anesthesia. Vice President George H. W. Bush discharged the powers and duties of the presidency during his incapacity, serving as acting president until later that day, when Reagan reclaimed his authority. The next to do so was George W. Bush, who underwent a colonoscopy procedure on June 29, 2002, and again on July 21, 2007. Vice President Dick Cheney temporarily became acting president on both occassions. Acting President of the United States An Acting President of the United States is an individual who legitimately exercises the powers and duties of the office of President
President pro tempore of the United States Senate former vice president Walter Mondale, who sought his former Senate seat in Minnesota in 2002, is the only one to have tried. Andrew Johnson is the only former president (1865–1869) to have subsequently served in the Senate (1875). George J. Mitchell was elected deputy president pro tempore in 1987, because of the illness of president pro tempore John C. Stennis, similar to Metcalf's earlier designation as permanent acting president pro tempore. The office has remained vacant since 1989 and no senator other than Humphrey and Mitchell has held it since its creation. Mitchell is the only person to have served