Did you know that the order of succession was established by the 25th Amendment to the US Constitution? It's true! And, the succession law has been amended several times over the years to reflect changes in the government. For example, the Secretary of State used to be next in line, but now they're way down the list.
The succession of the presidency is also filled with funny facts and anecdotes. Like, did you know that President Lyndon B. Johnson was sworn into office on a plane, after President John F. Kennedy's assassination? Or, that Vice President Gerald Ford was the first unelected Vice President to become President - it's a pretty cool story.
Presidential Succession Definition