Political infighting has shut down the government before. But this time, congressional Democrats and Republicans are further apart ideologically than at any time in the last 80 years.
One way political scientists track ideological trends in Congress is with DW-NOMINATE scores. These scores, developed by political scientists Keith Poole and Howard Rosenthal, are calculated by analyzing how individual members vote on economic issues over the course of their career. Members are then assigned a score between minus-one and one — where negative scores are associated with liberal views, positive scores are associated with conservative views and zero represents dead-center.
The closer a member’s score is to one, the more conservative their fiscal policy positions, and vice versa. Sen. Elizabeth Warren (D-MA), the most liberal member of the Senate, has a score of -0.74; Sen. Tommy Tuberville (R-AL), the most conservative senator, has a score of +0.94.
CNS analyzed the economic ideologies of every member of Congress going back to the end of World War II. Here are three key takeaways.
Congressional Democrats and Republicans have never been further apart on fiscal policy.
The current Congress is just 10 months old, but economic voting patterns put it on track to be more politically polarized than any Congress in the post-war era.
Between the mid 1940s and late 1970s, the average ideological score of Republicans in both chambers of Congress never strayed far from +0.3. A score of +0.3 now represents relative centrism, roughly lining up with the score of the third-least conservative Republican senator and the bottom 25% of Republican representatives in Congress now.
Democrats saw more ideological movement in the post-war period, but by the early 1960s, Democrats in both chambers were, on average, about as far left of center as Republicans were right.
Partisan ideologies began shifting further and further away from the center in the early-to-mid 1980s, with polarization becoming evident across the political spectrum.
Polarization has been considerably more pronounced on the right, with House Republicans moving as far to the right in the last 14 years as House Democrats have moved to the left in the last 45. Republicans in the Senate have moved as far right in the last six years as Senate Democrats have left in the last 20.
Up until the ‘90s, there was quite a bit of ideological crossover between the two major parties, and neither conservative Democrats nor liberal Republicans were particularly rare. In 2002, a Democratic congressman from Georgia, Sen. Zell Miller, was almost twice as far from the average Democrat as from the average Republican.
But Congress hasn’t had a right-of-center Democrat since Reps. Bobby Bright (D-AL) and Walt Minnick (D-ID) left office 15 years ago. The last left-of-center Republican — Constance Morella (R-MD) — left Washington in 2002.
Ideological movement varies from state to state
Some states aren’t seeing the congressional polarization that others are.
Maine, for example, is less polarized than ever. Even as the rest of Congress strays further from the center, the Pine Tree State has maintained its reputation for centrist politics: the average Republican is as far from center as Maine’s most polarized members are from one another.
The state’s representation in Washington includes Sens. Susan Collins and Angus King — the least conservative Republican in the Senate and the most centrist left-leaning senator — as well as Rep. Jared Golden, the second-least liberal Democrat on the Hill. The state’s only other congressperson, Rep. Chellie Pingree, is a Democrat who is ideologically on par with the average score of House Democrats.
Meanwhile, 20 states are only represented by members of one party. Five of the six states in New England, plus New Mexico, Delaware and Hawaii, are represented in Congress only by Democrats or liberal independents. Twelve states, most of them located in the center of the country, are represented only by Republicans.
Government shutdowns have become longer and more frequent as Congress has become more polarized.
Prior to 1980, Congress had failed to pass a spending bill before the previous one expired on a handful of occasions, but government shutdowns were unprecedented. Although Congress was technically required by law to shut down the government in that scenario, it never did. But the Carter administration’s attorney general ruled in April 1980 that the government did, in fact, have to shut down if Congress couldn’t agree on a spending bill.
The government partially shut down for the first time five days later, and another seven times over the next seven years. None of those eight shutdowns lasted longer than three days.
The government then shut down in 1990, before partially shutting down twice more in the mid ‘90s. The first two lasted under a week; the third three weeks. At that point, Democrats and Republicans in the Senate were, on average, 10% further apart ideologically than they had been 15 years prior; the divide between the parties in the House had grown by 30% over the same period.
When the government shut down for 17 days in 2013, the ideological gap had expanded by another 25% in the Senate and 15% in the House.
The first Trump administration saw two government shutdowns — including one lasting over a month — as Republicans in both the House and Senate found themselves over 70% further from center than in 1980.
Today, as the government shutdown continues into its fourth consecutive week, the parties find themselves further apart than ever, though the effects of polarization remain lopsided.
The ideological divide in the Senate stretches over 0.9 points — meaning the average Senate Republican is nearly as far from the center as they were from the average Senate Democrat 45 years ago. The gap between Democrats and Republicans is similar in the House, with average members of each party over 1 ½ times further apart ideologically than in 1980.