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How the Senate’s Long-Term Equilibrium Could Shape Democratic Decisions on the Filibuster


— A majority of states are now either solidly Republican or solidly Democratic on the presidential level, and the party a state prefers for president increasingly has a big edge in winning the state’s two Senate seats. Given these patterns, it’s possible to game out the basic contours of what the Senate “should” look like in the near future, barring some unexpected upheaval.

— Allocating Senate seats based on current presidential preferences produces an equilibrium of about 53 seats for the Republicans and 47 seats for the Democrats.

— This complicates the Democrats’ decision on whether to ditch the filibuster, because in a chamber where they may end up spending a lot of time in the minority in the future, ending the filibuster may destroy one of the few points of leverage the party would have.

The generic Republican edge in the Senate

With their party in control of the White House and the House, Democrats have been chafing at their bare majority in the Senate, currently a 50-50 tie that can be broken by Vice President Kamala Harris. Given the party’s ambitious agenda — from infrastructure and safety-net spending to election and policing legislation — more than a few Democrats, both inside and outside the chamber, have fantasized about a Senate without a filibuster.

The filibuster is a tool that can be used by a Senate minority to stall legislation unless 60 senators vote to take up the measure. In our era of intense partisanship, Democrats harbor little optimism that their most desired bills can secure the backing of 10 Republicans, which is the bare minimum required even if all Democrats are united behind a particular measure. So, with the exception of either non-controversial bills or ones where the “reconciliation” rule allows simple-majority passage, the Senate has become a legislative graveyard. But if the filibuster were to disappear, it might not be.

The filibuster isn’t etched in stone. In 1917, the Senate voted to empower a supermajority of 67 to cut off a filibuster and move on to other business, using a motion known as “cloture.” Then, in 1975, the Senate voted to lower the supermajority to its current 60 votes.

To dismantle the filibuster either partly or fully wouldn’t take 60 votes. Using a method known as the “nuclear option,” a bare majority can change the rules. For decades, there was a norm against doing so, but by now, both parties have used it — by Democrats, to end the filibuster on presidential appointments other than the Supreme Court, and, a few years later, by Republicans to end the filibuster for Supreme Court nominations.

To be sure, getting rid of the filibuster wouldn’t be easy. One Democratic senator, Joe Manchin of West Virginia, is strongly opposed to the idea of ending the filibuster, and others have expressed concerns about ending it, including Kyrsten Sinema of Arizona. In the Senate’s current lineup, a “no” vote by either Manchin or Sinema would be enough to kill any effort to ditch the filibuster.

But the existence of the nuclear option means that, at least in theory, there’s a way to do it. And given that reality, one urgent question is whether it would be in the Democrats’ long-term interests to pursue that course.

A look at partisanship patterns in the Senate can shed some light on that question.

In recent years, most of the 50 states have become either solidly Republican or solidly Democratic on the presidential level; these days, only a handful are “swingy.” Equally important, a state’s presidential preference increasingly gives that party a big edge in winning its Senate seats. Put simply, there are few states today that vote one way for president and another way for senator.

With this knowledge, it’s possible to game out the basic contours of what the Senate “should” look like in the near future, barring some unexpected upheaval.

There are 23 states that Donald Trump won in 2020 by at least five points:

Alabama, Alaska, Arkansas, Idaho, Indiana, Iowa, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, North Dakota, Ohio, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Utah, West Virginia, and Wyoming.

And there are 19 states that Joe Biden won in 2020 by at least five points:

California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, Virginia, and Washington state.

This leaves eight states where the Trump-Biden margin was within five points:

Arizona, Florida, Georgia, Michigan, Nevada, North Carolina, Pennsylvania, and Wisconsin.

Let’s add to this list of close states a few additional ones that were close-ish, and which could be in the future. From the Republican list, let’s add Iowa, Ohio, and Texas; from the Democratic list, let’s add Minnesota and New Hampshire.

This leaves 20 solidly Republican states, 17 solidly Democratic states, and 13 battleground states.

If you allot two Republican Senate seats to the 20 solidly Republican states, two Democratic seats to the 17 solidly Democratic states, and one seat for each party from the 13 battleground states, then the basic, near-term equilibrium would be 53 seats for the Republicans and 47 for the Democrats. (This counts the chamber’s two nominal independents — Vermont’s Bernie Sanders and Maine’s Angus King — as Democrats.)

The Democrats, of course, are currently doing three seats better than this equilibrium benchmark.

They have managed to poach seats from two solidly Republican states: Manchin’s from West Virginia and Jon Tester’s from Montana. And they have also swept both Senate seats in four of the eight core battleground states: Arizona, Georgia, Michigan, and Nevada. That’s a stronger showing than the GOP, which had battleground sweeps in just two of the eight, Florida and North Carolina.

What does this mean? It means that the Democrats had to rely on a near-miraculous set of circumstances just to reach a 50-50 tie that can be broken by a vice president of their own party.

To do it, the Democrats had to hold what are effectively borrowed seats in West Virginia and Montana and win two Senate seats each in Arizona and Georgia (two states with entirely Republican Senate delegations as recently as 2018) as well as hold one of the two seats in Ohio, a state that’s increasingly challenging for Democrats.

It’s probably safest to assume that the Democrats won’t always be so lucky.

Are there ways Democrats can improve their position in the Senate? Yes, to an extent. In 2022, they will be gunning to flip GOP-held seats in Pennsylvania and Wisconsin, the two states with currently split delegations among the eight core battlegrounds. And they could up their game by poaching some seats in Florida, North Carolina, and Texas in future election cycles, all competitive states where Republicans currently hold both Senate seats.

But from today’s standpoint, there’s no guarantee that Democrats will be able to make all of these inroads into GOP territory — or, for that matter, keep their endangered red-state seats in hand.

So how do these calculations shed light on the filibuster?

If the long-run equilibrium for Senate Democrats is somewhere in the range of 47 seats, then, mathematically at least, the filibuster could serve as more of a hindrance to the GOP than to the Democrats. If the GOP is threatening to pass a bill Democrats detest, the existence of a filibuster means that Republicans — with something like 53 seats — would still need to get about seven Democratic votes to secure cloture.

That’s a decent bit of leverage. But if the Democrats got rid of the filibuster, that leverage — one of the few bits of leverage they may have as a minority party — would disappear.

Inevitably, there are some caveats.

One is the possibility, as we noted earlier, of an “unexpected upheaval.” The political environment can change. As noted above, Democrats holding two Senate seats in both Arizona and Georgia would have been far-fetched just a few short years ago. Prior to the 2018 cycle, few Democrats would have expressed much optimism about a seriously competitive Senate race in Texas, but the 2018 Senate race was close — thanks largely to an anti-Trump drift in the suburbs that couldn’t have been predicted a few years earlier.

The counter-argument is that, given the chamber’s staggered, six-year terms, upheavals like this would change the Senate’s composition only slowly.

Another caveat is the term we used earlier: “mathematically.” Ideological impulses can complicate this equation.

In general, Democrats are likelier than Republicans to favor ending the filibuster because it “stands in the way of using the federal government to address national problems,” said Steven S. Smith, a political scientist at Washington University in St. Louis who specializes in the Senate. “Liberals argue, with good reason, that popular programs, once established, will be difficult to repeal even with simple-majority cloture.”

Democrats could decide that the numerical calculations above are outweighed by other factors. “If you think that climate change, social justice, and fate of democracy are genuine crises, then taking a risk on future parliamentary disadvantage may seem like a risk worth taking,” Smith said.

Meanwhile, Democrats may not fear retribution from Republicans if they “go nuclear,” since Republicans — as opponents of large federal programs — may be reluctant to retaliate with any procedural changes that make it easier to pass new programs, Smith said.

In the end, the continued opposition of senators like Manchin and Sinema may make the anti-filibuster push moot. But as long as it remains a possibility, calculating the long-term Senate equilibrium at least makes clear to Democrats what the potential cost could be.

Louis Jacobson is a Senior Columnist for Sabato’s Crystal Ball. He is also the senior correspondent at the fact-checking website PolitiFact and is senior author of the Almanac of American Politics 2022. He was senior author of the Almanac’s 2016, 2018, and 2020 editions and a contributing writer for the 2000 and 2004 editions.