When can a vice president run for office?
A candidate for vice president of the U.S. does not run
separately. The VP candidate is selected as a running mate by the
candidate for president, and they run as a team. Back in the
beginning, they did run separately: the person with the most votes
was president, and the one with the second most was vice president.
That system didn't last very long; rivals who'd fought for election
didn't usually team up too well. (But it could happen within a
party!) A VP can run for president later if the person's party
selects him or her as the candidate or if the person decides to run
independently.