Senators on both sides are friends of the filibuster

Senate Republicans rebuffed President Trump’s Twitter demand on Tuesday for an end to the legislative filibuster. As long as the filibuster remains in place, it will be much harder for Republicans to push key elements of the Trump agenda through the upper chamber. Why are Republicans determined to save a 60-vote threshold that makes it more difficult for them to achieve their legislative goals?

One reason is tradition. “The Founding Fathers set it up this way,” Sen. John Kennedy (R-La.) said. Which isn’t quite true: the origins of the filibuster can be traced back to an 1806 rule change, but that still means the Senate survived its first 15 years without the filibuster.

{mosads}In any event, tradition wasn’t enough to stop the Senate from lowering the threshold for cutting off debate from two-thirds to three-fifths in 1975. Tradition also didn’t stop Senate Democrats from eliminating the filibuster for confirmations to cabinet posts and lower court judgeships in 2013, nor did it stop Senate Republicans from going a step further last month and ending the filibuster for Supreme Court nominees. Much to Tevye the milkman’s dismay, tradition can’t be the whole story.

A second explanation for the filibuster’s survival comes from game theory. Republicans are willing to keep the legislative filibuster while they are in the majority so that Democrats do the same when they are in the majority.

Arguably, that redounds to the benefit of Republicans in the long run. To a first approximation, Republicans want a smaller government and Democrats want a bigger one. Government growth generally requires new legislation, and so Republicans gain from a rule that makes legislation harder to pass. 

But shrinking the size of government generally requires new legislation too. Thus, it’s not so clear that the filibuster makes government smaller. What it definitely does is make the status quo stickier. The survival of the filibuster reflects an implicit agreement between the parties not to make changes that are too extreme in either direction.

A third reason for the filibuster’s persistence is that moderates don’t want it to go away. Think about the problem from the perspective of Sen. Susan Collins (R-Maine), probably the most moderate member of the Republican caucus. Without the filibuster, Republicans wouldn’t need Collins’s vote to pass legislation. It’s the 60-vote threshold that keeps her relevant. No wonder, then, that Collins has emerged as the leader of a bipartisan effort to keep the filibuster in place.

Last but not least, the filibuster forces the Senate to rely on the budget reconciliation process, which allows a simple majority to pass certain revenue-related bills. Reconciliation comes with its own set of rules — one of which is that a reconciliation bill can’t add to the deficit outside of the so-called “budget window” (usually five or 10 years).

To decide whether a bill increases the deficit outside the budget window, the Senate turns to the chair of the Budget Committee, who usually — but not always — relies on estimates from the nonpartisan Congressional Budget Office and the Joint Committee on Taxation. 

For senators who care about keeping the deficit under control, reconciliation is a reason for maintaining the filibuster. Having a simple majority rule for reconciliation bills and a 60-vote threshold for everything else makes it harder to pass legislation that increases future deficits than to pass legislation that is revenue-neutral over the long run.

Republican deficit hawks — who are an endangered species, but not yet extinct — therefore have an interest in the filibuster’s survival. If the filibuster goes the way of the dodo, and anything can pass with a simple majority, then there will be no reason to rely on reconciliation. The fiscal discipline imposed by the reconciliation process will be lost.

Meanwhile, the Budget Committee chair — deficit hawk or not — has an incentive to preserve the filibuster too. The more that the Senate relies on reconciliation, the more important is the role that the Budget Committee and its chair play. Perhaps predictably, current Budget Committee Chair Mike Enzi (R-Wy.) has signed onto Sen. Collins’s filibuster preservation effort.

Ultimately, it requires only 51 votes, or 50 plus Vice President Mike Pence as a tiebreaker, for the Senate to end the legislative filibuster for good. But assembling that simple majority won’t be easy — now or in the foreseeable future. Tradition aside, individual members of the majority caucus have much to lose from the legislative filibuster’s demise. For moderates, deficit hawks, and the Budget Committee chair, the filibuster is a source of power even as it stymies the majority party’s program.

Daniel Hemel is an assistant professor at the University of Chicago Law School. @DanielJHemel. David Herzig is a professor at Valparaiso University Law School. @professortax.

The views expressed by contributors are their own and not the views of The Hill.