As in, 50 Democrats, 50 Republicans, and no clear majority. What happens then?
The short answer is, whatever the current makeup of the Senate wants, within some constraints. The long answer is, well, slightly longer.
Article I of the Constitution (the part that talks about the legislature) discusses how the House of Representatives and the Senate should be organized, how their members should be chosen, and the rules for voting in a small number of instances (for example, the Constitution specifically states that you need a two-thirds majority in the Senate to convict in an impeachment trial, or to remove a Senator from office). It also dictates that the Vice President is the formal head of the Senate, but that since the VP will presumably be busy with other duties (including filling in for the President), senators elect a “president pro tempore” to serve in their place. Unlike the president pro tempore, who is an elected senator like the rest and therefore can cast votes like anyone else, the Vice President “shall have no vote, unless [the Senate] be equally divided.” Beyond that, and a few other requirements, the Constitution otherwise states that “each House may determine the rules of its proceedings,” thus leaving it to each iteration of Congress to come up with its own manner of organization.
So basically, if you ignore the last 115 Congress’ worth of rules and precedents and just go by what’s in the Constitution, you could assume that in the case of a Senate divided between 50 Democrats (or people who caucus with the Democrats) and 50 Republicans (or people who caucus with the Republicans), the Vice President could step in on every party line split to vote in favor of his or her side, thus rendering that party effectively in the majority.
This would be, in a word, ridiculous.
Aside from being completely impractical and also going against how the Senate is supposed to work (since you’d have to rely on a 101st member who wasn’t elected into the role), this method ignores the reality of the Senate as it works today… because, of course, when the Constitution was designed, there were no political parties in the Senate or anywhere else. When the first three-or-so Congresses cast their votes to elect their officers, they were voting as individuals, as opposed to as members of a political party or caucus. The political party system is not written into any of our founding documents, so this problem is seemingly impossible to solve in a rational way using just those texts (sorry, Scalia’s Ghost).
These days, of course, party politics are the name of the game, and being in the majority gets you and your party all sorts of exciting powers and privileges, including but not limited to:
- Getting to pick the de facto head of the Senate – which isn’t the Vice President, and isn’t even the president pro tempore (a largely ceremonial honor usually awarded to the most senior member of the majority party), but rather, the majority leader.
- Setting the daily legislative agenda, which is one of the majority leader’s primary jobs. In practice, this means the majority leader can control what gets discussed and voted upon.
- Having the privilege of offering amendments first to any bill. This is one of the perks that goes along with the post of majority leader.
Holding the majority of seats in committees. Under current Senate rules, the percentage of seats on any given committee given to each party are determined by the percentage that that party holds overall, so the greater a majority your party has, the greater number of seats you have on any given committee.
- Committee chairs are always members of the majority party – and as the chairs are responsible for setting committee business and deciding what gets to move out of committee for consideration by the floor (here’s looking at you, Chuck Grassley), representatives from the majority party exercise a significant amount of control over what the Senate gets done.
So how do you decide which party gets to exercise these various controls when both parties are tied?
To be honest, I wouldn’t even know where to look, beyond the constitutional argument above…. if not for the fact that this has happened recently enough that there is a pretty solid and mutually-accepted precedent to follow (it also happened in 1881, but only for a few months, and by all reports they didn’t come up with anything worth treating as controlling precedent). Sixteen years ago, for the first five months of 2001 during the first term of George W. Bush’s presidency, the Senate was split evenly between Democrats (and people who caucused with the Democrats) and Republicans (and people who caucused with the Republicans). To make sure that the 107th Congress did not grind to a partisan halt, Democratic leader Tom Daschle and Republican leader Trent Lott came up with a unique power-sharing arrangement, the likes of which had not been seen before or since. Here’s what they did:
- During the time that they were divided 50/50 – January 3, 2001 to June 6, 2001 – it was acknowledged that under the constitutional provision that the Vice President gets to cast tie-breaking votes, the party of the VP was officially the party in the majority. That meant that from January 3 to January 20 (before Bill Clinton left office), the Democrats were in the majority, and from January 20 to June 6 (from George W. Bush’s inauguration until James Jeffords left the Republican party to caucus with the Democrats as an independent, giving them a 51 vote majority), the Republicans were in charge.
- Under normal circumstances, the majority has a greater budget to hire aides. Under this agreement, the funds were split equally so both parties could have staffs of equal size.
- As per the standing rules of the Senate, the party makeup of committees was divided evenly between the two parties. Since they were still technically in the majority, the Republicans retained the committee chairmanships.
- That said, if there is a tied vote in committee on whether or not to bring a bill to the floor for a vote, both the majority and minority leaders had the power to move the bill out of committee. Under normal circumstances, a tied vote would mean a bill did not move forward.
- Both majority and minority leader (in that order) had the opportunity to offer amendments to bills, although neither could offer so many amendments so as to block out any amendments by the other party (yes, this is a real legislative strategy available to the majority leader).
- These rules were to stay in effect until such time as one party or the other gained a majority of seats, in which case the organization of leadership and committees and funds would revert to normal, in favor of the party with the now-clear majority.
While neither party got everything they wanted – Democrats pushed really hard for co-chairmanships on all committees, which they ultimately did not get – and Republicans were loathe to give up one iota more power than they absolutely needed to, the plan was voted into effect and the Senate had a reasonably productive first few months. Looking back at articles from before the 2016 election, when a tied Senate seemed (blissfully) plausible, it seemed like both sides – or at least McConnell, who expected to be on the opposite side of the aisle from the tie-breaking 51st vote of a Vice President Kaine – were ready to enter into a power-sharing agreement based on the 2001 model. As McConnell told reporters, “We know we had that 16 years ago – the Senate, after the 2000 election, was 50-50… I think if we ended up 50-50, that we would simply replicate what we did in 2000.”
So… by the best of my estimation, there’s the answer. Although the Senate is well within its constitutional rights to set its own rules, at least for the time being, we have a generally successful precedent to follow if the Senate winds up, after some future election, with a 50/50 party split.