Congress can confirm a new Vice President, but if Congress couldn't operate due to an emergency like the attack on the Capitol, then there would be no one to fill in the the Vice President. Why is there no Vice Presidential line of succession?
The Vice President has exactly two jobs according to the Constitution:
- To preside over the Senate, breaking ties if and when necessary, but otherwise not voting or doing much else of substance.
- To become President or Acting President pursuant to the 25th Amendment.
#2 is not relevant here as it is part of the Presidential line of succession (which has numerous backup options if the VP is unavailable), so that leaves #1. But if we descend from the platonic ideal of "what the Constitution says" into the real world, the VP in fact spends little time presiding over the Senate, except when their casting vote is needed (this is more common when the Senate is closely divided, as you might expect). Instead, they spend most of their time facilitating the goals of the President. This often involves conferring with people such as lawmakers, cabinet members, and other federal officials, as well as a variety of other unglamorous behind-the-scenes tasks. Most of these tasks boil down to various forms of planning, negotiation, and coordination of the administration's policy agenda, and as a result, no Constitutional authority is required to carry them out (which is why the Constitution does not describe any of these tasks explicitly). Meanwhile, the Senate elects its own President pro tempore, who presides in the VP's absence (or further delegates that task to someone else).
So there are two reasons not to have a VP line of succession:
- As Rick Smith points out, the VP can't do their job very effectively if they do not share the President's policy goals. It's therefore preferable to let the President select a VP explicitly.
- If Congress is unable to come into session, then the Senate doesn't need anyone to preside over them. If they can come into session, but don't want to confirm a new VP for whatever reason, they could just elect a President pro tempore and carry on as usual. Unlike a vacancy in the office of the President, a vacant VP office is not an emergency, as the VP is not responsible for any particularly important Constitutional functions. It therefore makes more sense to just leave the office vacant for however long it takes to get a new VP confirmed.
The major purpose of the office of Vice-President is to have someone to succeed the President at need. Since there is a Presidential line of Succession specified by law in the case where there is no Vice President, and since a new VP can be confirmed by Congress, there is not an obvious need for a separate line of succession to the VP.
Why is there no Vice Presidential line of succession?
Were there a line of succession, the vice president could be of a different party or, in other ways, incompatible.
During the consideration of the Twenty-Fifth Amendment, it was decided that the president should nominate a person to be their vice president. This was primarily for compatibility — the same reasons that a presidential candidate chooses a vice presidential candidate at a nominating convention.
This is explained further in the relevant part of the report.
Section 2 is intended to virtually assure us that the Nation will always possess a Vice President. It would require a President to nominate a person who meets the existing constitutional qualifications to. be Vice President whenever a vacancy occurred in that office. The nominee would take office as Vice President once he had been confirmed by a majority vote in both Houses of the Congress.
In considering this section of the proposal, it was observed that the office of the Vice President has become one of the most important positions in our country. The days are long past when, it was largely honorary and of little importance, as has been previously pointed out. For more than a decade the Vice President has borne specific and important responsibilities in the executive branch of Government. He has come to share and participate in the executive functioning of our Government, so that in the event of tragedy, there would be no break in the informed exercise of executive authority. Never has this been more adequately exemplified than by the uninterrupted assumption of the Presidency by Lyndon B. Johnson.
It is without contest that the procedure for the selection of a Vice President must contemplate the assurance of a person who is compatible with the President. The importance of this compatibility is recognized in the modern practice of both major political parties in according the presidential candidate a voice in choosing his running mate subject to convention approval. This proposal would permit the President to choose his Vice President subject to congressional approval. In this way the country would be assured of a Vice President of the same political party as the President, someone who would presumably work in harmony with the basic policies of the President.