How Tuesday’s Primary Election in Alabama Could Shape the Future of the Senate—For the Worse

By Jordan M. Ragusa

A rare off-year special election in underway in Alabama to fill the Senate seat vacated by Jeff Sessions, Donald Trump’s attorney general, following his twenty year career in the upper chamber. According to Ballotpedia, just three off-year Senate special elections have occurred since Sessions first won election in 1996.

Although the general election isn’t until December 12, Tuesday marks the pivotal GOP primary runoff. In this deep-red state, most expect the victor to win the seat in December. Governor Robert Bentley selected Alabama’s attorney general, Luther Strange, to succeed Sessions. Despite having the governor’s endorsement, and being the de facto incumbent, Strange is facing a strong challenge from Roy Moore. Most polls indicate that Moore—the state’s controversial former chief justice—is in the lead heading into the runoff election. Polling off-year contests is notoriously difficult, however.

While the race is interesting for various reasons, I want to focus on the fact that the winner will shape the functioning of Senate for years to come. Given the power of individual senators to obstruct the chamber’s business, coupled with the GOP’s razor thin margins on key votes like the ACA repeal(s), Tuesday’s winner could decide the fate of major legislation in the 115th Congress and beyond. The victor could also tilt the balance in the ongoing feud between the establishment and anti-establishment wings of the GOP. Roy Moore is regarded as the quintessential outsider, a firebrand who has publically feuded with Mitch McConnell, while Strange is the establishment favorite. Lastly, Senate norms play a critical, albeit seldom appreciated, role in the upper chamber’s operation. Tuesday’s winner could be a key voice in institutional fights over the filibuster and the use of blue slips.

An optimistic view is that Sessions’ replacement will “fix” the upper chamber. Such claims are ubiquitous. Americans routinely claim that if we “just had new members, fewer career politicians, and term limits, Congress’s problems would be solved.”

Yet the opposite is most likely true, unfortunately.

Among people who study the institution, the consensus view is that Congress is deeply polarized and that the increase in polarization has caused problematic levels gridlock. While people tend to overstate the extent to which Congress is “broken,” as Matt Glassman argued in a recent Legbranch.com article, there is no denying the historic levels of polarization and gridlock in the contemporary Congress. On these points, see research by Poole and Rosenthal, Binder, and Mann and Ornstein.

If we think through the process by which polarization occurs, there are two possibilities: (1) member adaptation and (2) member replacement. Adaptation occurs when a lawmaker’s roll-call behavior becomes more conservative or liberal over the course of their career. In other words, lawmakers become more extreme in their behavior the longer they serve in the chamber. Replacement occurs when lawmakers retire, resign, or die in office, and are replaced by new members who are more extreme than they were. In other words, moderates leave Congress, and ideologues enter.

Which is a bigger cause of polarization, adaptation or replacement? And how does this relate to Tuesday’s election in Alabama?

If the answer is adaptation, Alabama’s special election could be a good thing for the functioning of the Senate to the extent that a senator who moved to the right over the course of his career may be replaced by a moderate. If the answer is replacement, however, Alabama’s special election may exacerbate polarization if a senator with a reliability conservative voting record is about to be replaced by someone even more conservative.

Using Nokken and Poole’s dataset, which scales the liberal and conservative direction of each senator’s roll-call record, I estimated the average size of replacement and adaptation (on the y-axis) in each decade since the 1960s (on the x-axis). For adaptation, values greater than 0 indicate the average member moved to the extremes (further left or right) from one Congress to the next (less than 0, the typical member moved to the center). For replacement, I matched each new senator in their first term with the senator they replaced. Values greater than 0 indicate the new senator was more extreme in their roll-call behavior compared to the exiting senator (less than 0, the typical replacement was more moderate).

What we see in the chart above is quite stark. Although lawmakers do indeed move to the extremes over the course of their career, that movement is gradual. In fact, the adaptation trend line is only slightly above the zero line for the entire time series. Replacement effects are large, by comparison, with the effect increasing over time.

In the 1960s, first-term senators tended to be more moderate compared to the senator they replaced. In the 1970s, there was little difference between the polarizing effects of replacement vs. adaptation. Beginning in the 1980s, however, replacement had a large polarizing effect compared to adaptation. As we can see in the chart, this disparity accelerated in the 1990s, a pattern that continued in the 2000s.

In sum, the largest cause of the Senate’s polarization is the replacement of career lawmakers with new members who enter the institution further to the left or right than the senator they replaced. It should be noted that this pattern is consistent with established findings in the congressional literature. Sean Theriault has written about this very topic in an article (see here) as well as in his book about polarization in Congress (see here). I have written about how the Senate’s polarization is due to replacement by lawmakers who first served in the House, arguing that representatives learn partisan norms and continue those extreme behaviors after switching chambers (see here). Research by Danielle Thomsen—cited in an article on Legbranch.com the other day—finds that fewer moderates are running for election in the contemporary era and are also more likely to retire early (see here).

In closing, there is little evidence that “throwing the bums out” and the retirement of “career politicians” will help “fix” Congress’s dysfunction. If anything, the evidence suggests the opposite is true: newly elected lawmakers are typically more extreme than the members they replace, with that polarizing effect contributing to Congress’s gridlock. In the context of Tuesday’s special election in Alabama, much is at stake as far as the future of the Senate, not only in terms of legislative productivity, but also vital Senate norms. Given his reputation as a “disruptor” and favorite of the “alt-right,” a victory by Roy Moore would no doubt exacerbate the Senate’s institutional challenges. But even if Luther Strange proves the polls wrong and wins Tuesday’s runoff, there is some evidence that he would be equally if not slightly more conservative than Jeff Sessions. Two decades ago, when Sessions won his first election, it was unthinkable that a replacement could be further to his right. Yet this is where we are in American politics.

Jordan M. Ragusa is an associate professor of political science at the College of Charleston, where he directs the college’s American Politics Research Team and is a research fellow in the Center for Public Choice and Market Process.