Why the Filibuster Suits the GOP Just Fine

Vikram David Amar: How to—carefully—surmount the Electoral College

What share of the vote would either party have needed to reach a filibuster-proof 60 seats? By shifting the vote in each of the 100 elections by the same number of percentage points until Democrats or Republicans were ahead in 60 races, we found that Democrats would have needed to win 55.8 percent of the national vote. Republicans would have needed to win only 50.2 percent of the vote to escape the zone—barely a popular majority at all.

We found a similar advantage for Republicans in every year since 1980. The advantage, 5.6 percentage points in 2020, averaged 3.4 percentage points. No wonder, then, that Republicans support the continued use of the filibuster. They are always closer to overcoming it than Democrats, irrespective of their appeal to voters.

The graph above shows the Zone of Legislative Death as a white band. Within this band is plotted the actual Democratic 100-seat popular vote. The color of the dots on the right panel indicates which party ended up in control of the Senate. Only once since 1980 have Democrats had a filibuster-proof majority—for six months, between the Minnesota Democrat Al Franken’s election in July 2009 and the Massachusetts Republican Scott Brown’s election in January 2010. And during the entire four-decade period, the total Democratic vote percentage has stayed between 49 percent and 54.5 percent, always below the necessary 55.8 percent.

Although Republicans do not need as much support to achieve 60 votes, getting there is still nearly out of reach because they usually win fewer votes nationally than Democrats. (In fact, Republicans have never once achieved 60 seats in the period since 1980.) But exceptions to the filibuster rule have been carved out that allow two major Republican policy priorities: cutting taxes and confirming federal judges. For Republicans, then, the status quo gives satisfactory results. For Democrats, current levels of partisan loyalty and obstruction guarantee that virtually no other bills can pass. The net result is a system that preferentially blocks one side’s goals.

The Zone of Legislative Death has widened over the years. In the 1980s, the zone was, on average, 3.8 percentage points wide. Since 2010, it has widened to 6.4 percentage points. This gulf widened because individual states have become more strongly partisan, leaving fewer competitive Senate seats.

Setting aside the filibuster, the modern Senate is strongly anti-majoritarian. Since 1980, Democrats have won the 100-seat popular vote 18 out of 21 times. But they gained control of the chamber in only nine of those cases. Using our extrapolation method, we calculate that an evenly divided national popular vote in 2020 would have given Republicans 59 seats. This nine-seat bonus arises from the fact that many Democratic votes are packed into high-population states such as California and New York, whereas Republican votes are distributed more efficiently in low-population states such as Wyoming and South Dakota. The correlation between partisanship and population density has held for 60 years, and is unlikely to go away soon.