A demonstration against repealing the Affordable Care Act is held on Capitol Hill on June 21. (Photo by Astrid Riecken/Getty Images)

Republican senators are struggling with how to repeal and replace the Affordable Care Act. Is it just a tough issue — or does the Senate no longer have effective lawmakers?

Our new data analysis suggests that senators’ success in moving bills through the legislative process has declined markedly over the past several decades — undermining the Senate’s capacity to resolve public problems.

Senate “lawmakers” are in decline

To identify Senate “lawmakers,” we started by tracking all 69,398 bills introduced in the Senate between 1973 and 2014. We located who sponsored each bill, the bill’s importance and how far the bill moved through the lawmaking process.

Following a methodology we used for the House of Representatives, we created a Legislative Effectiveness Score for every member of the Senate in each Congress over that time. The average value is one. The senators with the highest scores over the past 40 years are, for Democrats, Howard Cannon (Nev.) in the 96th Congress (1979-1980), scoring 10.19, and for the Republicans, Orrin G. Hatch (Utah) in the 104th Congress (1995-1996), with 7.73. In contrast, the lowest-scoring senators throughout the past 40 years have been caretaker Democrat Harlan Mathews (Tenn.) in the 103rd Congress (1993-1994) and Republican Jeff Sessions (Ala.) in the 113th Congress (2013-2014), both scoring zero.

For the purposes of illustration, and to simplify our broader analysis a bit, let’s label as a “lawmaker” any senator who introduces at least one bill that becomes law during a two-year Congress. By this standard, less than half of minority-party senators are lawmakers.

And as you can see below, even among majority-party senators, the number of such lawmakers has fallen sharply since the 1970s. Throughout the 1970s and 1980s, about three-fourths of majority-party senators shepherded at least one bill into law. Today, barely half of all majority-party senators do so. (We leave out the 107th Senate (2001-2002), when party control was in flux and neither party had many lawmakers.)


Why and when are senators effective lawmakers?

Consistent with our analysis of Legislative Effectiveness Scores in the U.S. House, we find that senators are more effective lawmakers when they serve in the majority party and if they chair a committee or subcommittee.

That said, these institutional factors aren’t quite as important in the Senate as in the House. Two other factors matter more in the Senate: seniority and having relatively (but not overly) safe seats. What’s more, much as we found in the House, women in the minority party are more effective lawmakers in the Senate than are minority-party men.

Some senators rise to the top time and time again. We create a benchmark score for each senator, based on seniority, majority or minority party membership, and status as a committee or subcommittee chair. We label as “below expectations” those who fail to score even half as high as their benchmark, while those whose scores are 50 percent or more above their benchmark are ranked as “exceeding expectations.”

Between 1973 and 2014, nine senators exceeded expectations at least eight times, as you can see below:


The list includes Democrats and Republicans. To no one’s surprise, it includes the “Lion of the Senate,” Ted Kennedy, and policy maven Pat Moynihan. And it includes three current senators: Hatch, John McCain, and Dianne Feinstein. Between 1992 and 1995, all nine of these lawmaking giants served together. As recently as 2008, seven of the nine were all serving in the Senate. Effective young lawmakers have yet to rise to fill the void.

What would increase the number of effective lawmakers?

Encouraging more women to run for office could bolster the ranks of effective lawmakers, as women by our measure outperform men in certain contexts. Recruiting more candidates from among state legislators might also improve lawmaking, because we find that senators who previously served in “professionalized” legislatures (meaning full-time, well-paid and well-staffed assemblies) outperform their peers. Recruiting the most effective House members to run for the Senate would also help, because highly effective House lawmakers also tend to succeed in the Senate.

Institutional features also matter. In the House, we found that term limits placed on committee chairs undermined that chamber’s lawmaking effectiveness. Meanwhile, representatives who cultivate bipartisan relationships and co-sponsor bills are more successful at making laws than are partisans.

Some may discourage attempts to help Congress get better at passing laws. They might argue that gridlock is good, built into our constitutional system of checks and balances. But checks and balances only work if the United States has a functional Congress. Otherwise the president will step into the void. President Obama did so on issues including auto emissionsimmigrationforeign policy and climate change. President Trump is doing so in reversing those Obama initiatives and striking off in new directions.

As presidents issue sweeping rules, regulations, and executive orders, they are taking over Congress’s constitutional role: legislating. Without effective lawmakers, Congress will be unable to respond.

Craig Volden is professor of public policy and politics at the Frank Batten School of Leadership and Public Policy at the University of Virginia.

Alan E. Wiseman is the Cornelius Vanderbilt Professor of Political Economy, and professor of political science and law at Vanderbilt University.