Can a previously-elected president serve as a vice president in a different administration?
The 22nd Amendment states “no person shall be elected to the office of the President more than twice…” It makes no restriction about succeeding to the office. Therefore a prior two-term President who is elected to VP can succeed to be President again, and serve out the remainder of the deceased President’s term. But that promoted VP could not be elected again as President.
Actually, it states that NO ONE shall serve more than 10 yrs. as President. Which means if a President dies a year after he takes office and the VP takes over he can only run one more and be elected, due to the fact that a second elected term would put him over the limit (ie: Ford). In the case of LBJ, Kennedy was killed well over 2 1/2 yrs. into his first term, so LBJ could have run a second time and won and it would have been constitutional. And I do believe that as long as the former Pres had only one term (or half or less of a appointed term and an elected term) and is capable of being President, then it is stated that he can run as VP. But keep in mind that if a 4 yr. term would put him over the 10 yr. alloted amount, he would not be elegible.