John Tyler of Charles City, Virginia, became president in early April 1841 just a month after William Henry Harrison’s inauguration on March 4. General Harrison was elderly and in poor health and died of pneumonia and pleurisy after delivering a two-hour inaugural address in freezing weather and being caught in a rainstorm at the end of March. Thus, Tyler became the first man to serve as president without benefit of election.
Millard Fillmore became president a year and a half into his term as vice president when Zachary Taylor died in office in 1850. Andrew Johnson became president after Lincoln’s assassination in April 1865 and survived impeachment. Chester Arthur was elevated to president after James Garfield was shot in 1881 six months into his term.
Teddy Roosevelt became president in 1901 after William McKinley was assassinated six months into his second term. TR was reelected in 1904. Calvin Coolidge ascended to the presidency after Warren Harding died of a heart attack in 1923. He was reelected in 1924. Harry Truman and Lyndon Johnson both became president after the death in office of Franklin Roosevelt and John Kennedy, respectively. They were both re-elected. Gerald Ford took over after Richard Nixon resigned in 1974 (to avoid impeachment).
Why bring up all of those who became president without benefit of election to the post? With all of the legal matters hanging over Donald Trump, I submit his resignation to allow Mike Pence would’ve been his smartest move. After all, Gerald Ford immediately pardoned Richard Nixon upon becoming president, ending the divisive Watergate Era. Given Trump’s ego and inability to deal with reality, I don’t think we shall have to worry about any such eventuality.