Yes a former US President can run for office of Vice President of the United States. A former US President can run and be elected for any other type of office.
Theodore Roosevelt was a former US President and a candidate for that office when he was shot and wounded.
Such a president only exists in someone's imagination.
Clinton
If you are currently in office as the US President, and your term is or has been more than two years, you can run for one more term. The 22nd Amendment to the US Constitution, establishes a two term limit for the office of the US President.
No person can become president of the US again after completing 2 terms in office.
The correct title for a former president of the United States is "former President."
A US President's wife holds no office nor the powers of any office. She might, of course, influence her Presidential husband as part of their personal relationship, but the US President has a Cabinet of official advisors who help him run the country and make decisions. A president's spouse has nothing to do with that in any official way.
Because he decided to run for office and won the elections.
Former US President Ronald Reagan
(in the US) No. I believe we've even had (an) ordained president(s)
A person who wants to be president has to have lived in the US for 14 years, as well as to be born a citizen of the United States to run for the office.
No former US president died in 1970. Closest was Dwight Eisenhower who died Mar 28, 1969.