I was thinking about this for a while, and I couldn’t come to any satisfactory answer. Therefore, I pose it to you guys, in several parts.
If there are 50 of Party A and 49 of Party B, with 1 of Party C, is the person from party C required[/c] to caucus with either of the two parties? If so, I assume the Vice President, as President of the Senate, breaks the tie (if there is one) to determine the majority. I’m fine with that.
But say the above scenario (50-49-1) stands. If the Veep is a member of the party with 49 members, does that make it 50-50-1 if he elects to appear every day? Or is his party irrelevant unless there is a genuine tie?
If his daily presence does make it 50-50-1, does the Veep’s party become the majority party? For that matter, why would “daily presence” matter? Absenteeism is chronic among our elected officials. Could the Veep impose such a situation, or doesn’t he count? He’s a de facto Senator and the head of the entire legislative body. Is his role simply to act as a tiebreaker, or can he vote tomorrow if he wants to? I haven’t seen anything that gives a definitive answer.
From what I understand though, if there is a 50-50 split in the Senate, the party that the VP belongs to will be the majority party. At least as far as senate leadership, commitee chair assignments and such go.
I think this is partially correct. I think that the party of the VP gets a sort of quasi-majority in name - so they have the House leader, etc. However, I think the parties have to work out committee chair assignments and other details between themselves.
I seem to remember (without googling) that the last time it was 50-50, the two parties worked out a powersharing agreement. Oh, here you go - an article addressing this from '01.
The VP’s party will have a “majority” in a 50-50 split by virtue of the extreme likelihood that for purposes of selecting committee chairs and other such power grabs, each set of 50 Senators will vote for its own party and the VP will vote with his party.
On the first part of your question the answer is no. A senator is not required to declare for either parties caucus. He or she can declare himself as the leader of his own party caucus and vote correspondingly. It is, at this point, a ticket to irrelevance-ville but weirder things have happened.
For that matter, a senator from either party isn’t required to caucus with their party. They could say they would remain a D yet caucus with the R for whatever reason. Though I’m pretty certain anyone who tried that had better hope they tip the scales otherwise they’re going to get the chairmanship of the ‘Cleaning up the Senate Catbox’ committee or something.
A Senator need not caucus with either party, but ultimately must vote one way or the other to “organize the Senate” – that is, to elect officers and committee chairs. In your scenario, if C voted with A on an organizational resolution, it would pass 51-49. If C voted with B, the result would be a 50-50 tie, which the Vice President would break.
It has happened, in 1881. The Senate of that year included 37 Democrats, 37 Republicans, one independent who caucused with the Democrats, and one Readjuster (don’t ask), William Mahone of Virginia. Mahone ultimately sided with the Republicans, leaving Vice President Chester Arthur to cast the tie-breaking vote to organize the Senate on Republican lines.
Alas, that summer Garfield was assassinated, Arthur succeeded to the Presidency, and the Republicans lost their tie-breaker! (We don’t think of an assassination as removing a Vice President, but it does–and in 1881 there was no provision for appointing a replacement.)
The two parties then worked out a power-sharing compromise, much as they did in 2001, but on different lines: “Republicans controlled the committees and Democrats managed the patronage.”
These decisions can be FAR from mundane. The so-called Nuclear Option, which would have allowed the President’s nominees to the judiciary to be approved with a simple majority vote (as opposed to the 60 required to override a filibuster) required the President of the Senate (i.e. the VP) to rule that only a bare majority was needed to approve judges. Such a ruling can be sustained by a majority vote. Only the intervention of the “Gang of 14” short circuited the process in '05.