A little history lesson that may be of interest to some of you:
When JFK was assasinated, LBJ took office. There was no provision for appointing a VP, so there was none during the remainder of that term. The 25th Amendment was enacted to provide for a mechanism to put one in place should it be needed.
When Agnew was forced to resign to face criminal charges, Ford was nominated to become VP. Nixon was already in trouble and his eventual removal from office was anticipated. The democrats controlled congress, but Ford, a republican, was assured of confirmation because he had a broad base of support that crossed party lines.
There was a small faction of democrats led by Bella Abzug who went to the then speaker of the house, democrat Carl Albert, who by law was the next in line to the presidency after the VP. Abzug's faction proposed to Albert that the congress drag its feet on the confirmation of Ford so that upon Nixon's eventual resignation or removal from office, Carl Albert would become president.
Carl Albert was reported to have basically thrown them out of his office. He, like Ford, placed the good of his country above his personal gain. This moment is considered by historians to be as close to a coup d'etat as the US has ever come.
It has been said (by Ford at his inauguration, among others) that we are a nation of laws, not men. But it takes men of the caliber of Ford and Albert to see that it remains that way.