Supreme Court Justices Become Less Impartial and More Ideological When Casting the Swing Vote
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Policy Sep 13, 2018

Supreme Court Jus­tices Become Less Impar­tial and More Ide­o­log­i­cal When Cast­ing the Swing Vote

A new study sug­gests that jus­tices may treat cas­es dif­fer­ent­ly when giv­en a chance to shape policy.

Supreme Court robes swing on a clothesline.

Lisa Röper

Based on the research of

Tom Clark

B. Pablo Montagnes

Jörg L. Spenkuch

In her dis­sent­ing opin­ion on a land­mark 2018 Supreme Court case with major con­se­quences for orga­nized labor, Jus­tice Ele­na Kagan pulled no punches. 

The Court’s con­ser­v­a­tive-lean­ing fac­tion — com­posed of Jus­tices Ali­to, Roberts, Kennedy, Thomas, and Gor­such — had over­ruled a long-held prece­dent for no excep­tion­al or spe­cial rea­son, but because it nev­er liked the deci­sion,” she argued. It has over­ruled [the prece­dent case] because it want­ed to.” 

Read­ing that opin­ion, Jörg Spenkuch, an asso­ciate pro­fes­sor of man­age­r­i­al eco­nom­ics and deci­sion sci­ences at Kel­logg, thought that it might hold the answer to a long-stand­ing puz­zle about the Court. 

Since the 1940s, polit­i­cal sci­en­tists have known that the ide­ol­o­gy of a judge — whether con­ser­v­a­tive or lib­er­al — often pre­dicts which way he or she will vote. Less clear, how­ev­er, is why. Some have argued that judges earnest­ly try to enforce the law impar­tial­ly — as John Roberts stat­ed in his 2005 con­fir­ma­tion hear­ing: It’s my job to call balls and strikes, and not to pitch or bat.” In this view, con­ser­v­a­tives and lib­er­als come to dif­fer­ent rul­ings sim­ply because they inter­pret the Con­sti­tu­tion differently. 

But, as Kagan’s dis­sent hint­ed, there is anoth­er, more cyn­i­cal hypoth­e­sis: that judges are wannabe pol­i­cy­mak­ers active­ly seek­ing to push the law in the direc­tion of their choosing. 

The ques­tion is, how do you fig­ure out using data what is and isn’t true?” Spenkuch says. 

In a new paper with B. Pablo Mon­tagnes and Tom S. Clark of Emory Uni­ver­si­ty, Spenkuch sought to deter­mine if the idea that judges are pol­i­cy­mak­ers holds water. The team ana­lyzed votes by Supreme Court jus­tices on more than 8,500 cas­es since World War II. They found that when a jus­tice casts the decid­ing vote, his or her per­son­al beliefs sud­den­ly mat­ter far more. 

The effect of a justice’s ide­ol­o­gy on how he or she votes essen­tial­ly dou­bles when the vote is piv­otal,” Spenkuch says. 

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The results prompt seri­ous ques­tions about the neu­tral­i­ty of the judi­cial branch, since it sug­gests that a jus­tice may treat a case dif­fer­ent­ly just because it presents a chance for them to shape pol­i­cy. Our idea of a good judge is that of an impar­tial umpire,” Spenkuch says. But jus­tices in some cas­es dis­re­gard the role of the umpire in favor of that of the politician.” 

Supreme Court Decision-Making 

In the 1980s, Supreme Court schol­ars pio­neered a cre­ative way to ascer­tain a judge’s ide­o­log­i­cal lean­ings. Scour­ing edi­to­ri­als about a jus­tice pub­lished in major U.S. news­pa­pers in the months fol­low­ing his or her nom­i­na­tion, they deter­mined whether that indi­vid­ual was per­ceived as lib­er­al or con­ser­v­a­tive, and how far from cen­ter he or she fell. 

Strange as it may seem, this tech­nique has proved remark­ably effec­tive. A judge whom edi­to­r­i­al writ­ers depict as a mild con­ser­v­a­tive, or a hard­line lib­er­al, will often vote like one. 

But judges are not equal­ly par­ti­san in every case. Many rul­ings are 9 – 0, and even a stur­dy lib­er­al or con­ser­v­a­tive will occa­sion­al­ly side with the oppo­site camp. So why does ide­ol­o­gy mat­ter in some cas­es but not others?

The effect of a justice’s ide­ol­o­gy on how he or she votes essen­tial­ly dou­bles when the vote is pivotal.”

In the past, schol­ars have argued that ide­ol­o­gy comes into play when there are dif­fer­ing legal inter­pre­ta­tions involved, or because cer­tain lit­i­gants touch a nerve with par­tic­u­lar jus­tices. But Spenkuch and his col­leagues want­ed to test a new the­o­ry: that a judge votes more in-line with their ide­ol­o­gy when their vote mat­ters more. 

Spenkuch had sev­er­al rea­sons to sus­pect this. Not only do opin­ions like the Kagan dis­sent sug­gest that jus­tices rel­ish affect­ing an impor­tant prece­dent, he says, but the Court’s deci­sion-mak­ing process ensures that jus­tices know when they, per­son­al­ly, have an oppor­tu­ni­ty to do so. 

After the Supreme Court hears oral argu­ments, the jus­tices meet in pri­vate to dis­cuss the case at hand. Although no reporters are allowed in the room, mem­oirs from for­mer jus­tices describe what hap­pens next. They sit around the table and they talk in order of senior­i­ty about the case — what they think the legal argu­ments are, and how the case should be decid­ed,” Spenkuch says. 

Thus, every jus­tice will know how every oth­er jus­tice is plan­ning to vote and whether their own vote could be the decid­ing fac­tor in the case. 

In order to deter­mine whether their sus­pi­cion was cor­rect, the researchers turned to the Supreme Court Data­base, a mas­sive pub­lic col­lec­tion of detailed infor­ma­tion about every case since 1946. The data­base also includes attrib­ut­es of indi­vid­ual jus­tices, includ­ing indi­vid­ual votes and an ide­ol­o­gy score (com­put­ed with the news­pa­per-edi­to­r­i­al technique). 

The researchers used sta­tis­ti­cal meth­ods to deter­mine whether each judge reli­ably swung fur­ther towards one side when his or her vote was piv­otal ver­sus non-pivotal. 

What I mean by piv­otal’ is that, if you change your vote, hold­ing all else con­stant, the case would be decid­ed dif­fer­ent­ly,” he explains. So in a 5 – 4 deci­sion, every jus­tice in the major­i­ty is piv­otal — not just the medi­an justice.” 

Politi­cians in Robes” 

The researchers found that, when cast­ing a piv­otal vote, lib­er­al jus­tices are more like­ly to vote lib­er­al­ly while con­ser­v­a­tives are more like­ly to vote con­ser­v­a­tive­ly, com­pared to when those same judges cast a non-piv­otal vote. 

In short, jus­tices vote dif­fer­ent­ly when they real­ize that their vote real­ly matters. 

And the pat­tern becomes more pro­nounced for jus­tices who are more ide­o­log­i­cal­ly extreme. The researchers found that the more lib­er­al or con­ser­v­a­tive a jus­tice is, the more fre­quent­ly he or she votes in that direc­tion when cast­ing the decid­ing vote. 

Next, the researchers want­ed to break down why being piv­otal mat­tered so much. Was it sim­ply about who wins the case or about the prece­dent it sets when being cit­ed in future cases? 

To dis­sect these two fac­tors, they took advan­tage of the fact that a judge can agree with oth­er jus­tices about which lit­i­gant is in the right, but will dis­agree about why. In those instances, the judge writes a sep­a­rate opin­ion, in which he or she lays out his or her unique rea­son for the vote. When this hap­pens, sep­a­rate opin­ions are issued, and every jus­tice can choose which opin­ion to join. 

That means that there are times when a judge’s vote is not piv­otal for the out­come of the spe­cif­ic case but is piv­otal for set­ting case prece­dent. This is because for low­er courts to be bound by a Supreme Count opin­ion, five jus­tices need to have backed that opin­ion. So it is pos­si­ble for a case to have six cer­tain votes sid­ing with, say, the pros­e­cu­tion, but for those six jus­tices to be split 4 – 2 between Expla­na­tion A and Expla­na­tion B. In this case, one of the remain­ing jus­tices can become piv­otal if they join the four jus­tices, thus mak­ing Expla­na­tion A the precedent. 

Ana­lyz­ing these unusu­al cas­es, Spenkuch and his col­lab­o­ra­tors were able to parse whether piv­otal votes mat­tered because judges want­ed to shape prece­dents or because they want­ed to shape outcomes. 

And what we show is that both seem to mat­ter,” he says.

Con­sid­er­ing the Supreme Court Tiebreak­er Theory 

While these find­ings seemed to sup­port the idea that jus­tices are real­ly politi­cians in robes,” as Spenkuch puts it, there was an alter­na­tive expla­na­tion to con­sid­er. Promi­nent jurist-cum-econ­o­mist Richard Pos­ner has argued that in cas­es with ample ambi­gu­i­ty and strong legal argu­ments on both sides, judges’ ide­ol­o­gy is not so much a dri­ving moti­va­tion, but a nudge that can help make a tough decision.

In Posner’s view, the rea­son jus­tices vote ide­o­log­i­cal­ly is that they would like to call the balls and strikes, but they lack the nec­es­sary infor­ma­tion to do it,” Spenkuch says, so they let their ide­ol­o­gy take the place of that information. 

If this was the case, then judges may be more par­ti­san in piv­otal votes not because they are try­ing to impact the out­come, but because being piv­otal goes hand in hand with more ambi­gu­i­ty. That would mean that piv­otal jus­tices should become more polar­ized in espe­cial­ly ambigu­ous cases. 

So we looked at sit­u­a­tions where there should be more uncer­tain­ty on legal grounds,” Spenkuch says. 

The researchers iso­lat­ed the cas­es in which low­er courts had dis­agreed about the cor­rect rul­ing, sug­gest­ing that there was con­sid­er­able uncer­tain­ty in the law. In those cas­es, piv­otal vot­ers were actu­al­ly less ide­o­log­i­cal than in non­am­bigu­ous cas­es — the oppo­site of what Posner’s the­o­ry predicted. 

That, I think, lets us rule out Posner’s tiebreak­er expla­na­tion,” Spenkuch says. 

Not Umpires After All? 

Spenkuch believes that his find­ings fly in the face of how Supreme Court jus­tices try to present them­selves. Dur­ing con­fir­ma­tion hear­ings, no jus­tice ever admits that they’re inter­est­ed in mak­ing pol­i­cy,” he says, allud­ing to Roberts’s claim that judges sim­ply call balls and strikes.” 

The study casts doubt on that claim. And it pos­es a big ques­tion about the true role of the Court, since jus­tices may be chang­ing their votes based on how their col­leagues vote. 

There is a non­triv­ial num­ber of cas­es that would be decid­ed dif­fer­ent­ly if jus­tices did not vote strate­gi­cal­ly,” he says. It draws into doubt the notion of the Supreme Court as an insti­tu­tion where lit­i­gants come to get justice.” 

Featured Faculty

Jörg L. Spenkuch

Associate Professor of Managerial Economics & Decision Sciences

About the Writer

Jake J. Smith is a writer and radio producer in Chicago.

About the Research

Clark, Tom, B. Pablo Montages, Jörg L. Spenkuch. 2018. "Politics from the Bench? Ideology and Strategic Voting in the U.S. Supreme Count." Working paper.

Read the original

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