This is a list of the people in the line of succession to become President of the United States upon the death, incapacity, resignation, or removal of the acting president or president-elect. Who becomes President if Joe Biden dies? The first up is VP Kamala Harris, followed by the Speaker of the House Nancy Pelosi. In the unlikely event that the American President dies or leaves the office, this is the order in which other U.S. politicians would be in line for to become the Acting President.
The line of succession has only come into play a few times in American history. A few times, a vice president has become president when the President has died of natural causes, which has happened 4 times:
-William Henry Harrison died in 1841 after 30 days in office; he was succeeded by John Tyler
-Zachary Taylor died in 1850 after 1 year and 4 months in office; he was succeeded by Millard Fillmore
-Warren G. Harding died in 1923, 2 years and 4 months in office; he was succeeded by Calvin Coolidge
-Franklin D. Roosevelt died in 1945 after 12 years in office, 1 month into his 4th term; he was succeeded by Harry S. Truman
Several American Vice Presidents have also risen to the presidency following the assassination of the President. This has also happened four times:
-Abraham Lincoln was assassinated in 1865, 1 month into his second term; he was succeeded by Andrew Johnson
-James A. Garfield was assassinated in 1881, after 6 months in office; he was succeeded by Chester Arthur
-William McKinley was assassinated in 1901, 6 months into his second term; he was succeeded by Theodore Roosevelt
-John F. Kennedy was assassinated in 1963 after 2 years and 10 months in office; he was succeeded by Lyndon B. Johnson
The one other time a Vice President succeeded to the Presidency followed the resignation of Richard Nixon in 1974, after which Gerald Ford became President.
Gosh, that's actually a lot of Vice Presidents who became President, when you consider that there have only been 45 total American Presidents. So far. And in "Battlestar Galactica," Secretary of Education Laura Roslin was #43! in line before the Cylons surprise attacked the Twelve Colonies and killed the whole government. I guess I'm just saying: it doesn't hurt to be prepared.