The Supreme Court really is that partisan.

No matter what your personal politics, you cannot deny that Justice Antonin Scalia had style. For instance:

“This case, involving legal requirements for the content and labeling of meat products such as frankfurters, affords a rare opportunity to explore simultaneously both parts of Bismarck’s aphorism that ‘No man should see how laws or sausages are made.’”

In addition to humour, Justice Scalia brought a fighting spirit to his opinions — especially his dissenting ones — which struck some in the legal community as inappropriate. It was too political, too lacking in reverence for his learned friends on the bench when the Supreme Court is supposed to stand above partisan politics. Recent highlights included his dissents in the Obamacare case, King v. Burwell, where he accused the majority of “interpretive jiggery-pokery”, and the same-sex marriage case, Obergefell v. Hodges, where he described the majority opinion as being based on “the mythical aphorisms of the fortune cookie” and “couched in a style that is as pretentious as its content is egoistic”. There is a structural limit to the number of times you can insult your judicial colleagues in a single opinion, and if Scalia did not reach it, he certainly searched ardently.

We may not see dissents like his for some time. He relished the fight in a way that none of the remaining Justices do, and frequently accused other Justices of ‘judicial activism’ — making rulings based on personal or political considerations rather than on existing law. The form and substance of his statements made clear that he saw the Court as a political institution. But during each of their confirmation hearings, his fellow Justices had emphasized the law’s impartiality and the Court’s role as a humble interpreter. They portrayed themselves as apolitical, and most of the listening Senators would have perceived any deviation from this modest posture as grounds for rejecting a nominee.

It begs the question: which is right? Which is the Court — battleground or temple?

The answer should be pretty obvious. In reality, the Court is not above politics — if political leanings played no part in judges’ decisions, we would see an entirely different nomination process.

Fortunately, we live in revealing times. The death of a Republican-appointed conservative Justice under a Democratic president has the potential to shift the ideological balance of the Court strongly to the left, and the context of a chaotic presidential campaign has brought the Court to the fore. Congressional Republicans have spent weeks refusing to hold hearings on any Obama nominee, holding out for a Republican president after the November election. They’ve relied on increasingly tenuous claims about political precedent to argue that nominations and election years do not mix. Among the Democrats, Vice-President Biden has backed away at warp speed from a 1992 speech which seemed to endorse the Republicans’ position. Both sides of politics are looking for legitimate procedural reasons to do what is in their self-interest and appoint an ideologically similar nominee.

The academic evidence suggests this is a good idea on their part. In 1989, two American political scientists, Jeffrey Segal and Albert Cover, produced an iconic paper illustrating the influence of political ideology on Supreme Court justices’ voting records. They were able to predict how Justices voted with stunning accuracy, using an independent measure of their political beliefs on a liberal to conservative spectrum. The correlation, at it strongest, was 0.80 — keeping in mind that for social science, 0.30 is a large effect. This severely undermined the dominant ‘legal model’ of judicial decision-making; the idea that judges used legal factors like precedent to decide cases, rather than their own political views. The evidence on precedent is pretty shocking as well. Segal and Harold Spaeth later found that in the exact cases where respect for precedent should force judges to switch their ruling — where judges who had dissented from landmark rulings encountered the question again in a new case — they switched their position less than 10% of the time.

These findings are controversial in the legal community. And they should be — the Supreme Court is unelected and able to overrule the will of the democratic majority. Sometimes that’s good — minorities can need protection from majorities. But the Court’s authority to protect minorities comes from the Constitution and the Bill of Rights. The implied public bargain is that the Court is allowed to resolve contentious political questions, because it rules impartially based on shared founding principles. Which is, in practice, not really true.

Now, to be fair to the legal model, there is another layer of complexity we need to engage with before deciding it’s all a sham. To assume that judges’ interpretations of the law will be identical assumes the law is rationally determinate — meaning that one correct answer, and only one, is suggested by the law. However, there is another source of judicial variation we may wish to allow room for — judicial philosophy (a judge’s belief correct method of interpreting the law). An originalist will argue the Constitution’s meaning is the one intended by the Framers at the time of writing, while a contextualist will argue the meaning of its provisions shifts over time as society changes. Most lawyers see them as sitting within a spectrum of legitimate judicial approaches. I say most judges because a dyed-in-the-wool originalist and general curmudgeon like Scalia would fling a few choice insults at a contextualist. The systematic variation observed in Segal & Cover could possibly be explained by judicial philosophy; their measurement method for ideology (newspaper editorials about the nominees’ views) could be picking up variation which is driven by the third factor of philosophy. I suspect that the correlation between political ideology and judicial philosophy is in fact very high, and there are structural features in these belief systems why this might be the case. Originalism is grounded in the past and contextualism in social change, a distinction which maps well on to conservative and liberal political ideologies (both in the sense of their tolerance for rapid change, and in their substantive policy goals). Even if they are theoretically separate in a judge’s mind, judicial philosophy provides an effective shorthand for Presidents and Senators looking to select a nominee who will benefit their political projects.

Judicial philosophy also helps to muddy the water on the precedent finding; an originalist may claim their primary loyalty is to the founding document over precedent, and a contextualist may argue for the slow overturning of precedents which have become out of step with society.

So, where does this leave us? Perhaps the only thing we can safely conclude is that the law is not mechanical, and its meaning is not set in stone. There exists a spectrum of acceptable ways of judging, and the ambiguity created by this procedural spectrum could allow room for political bias (conscious or unconscious) to shape judges’ rulings. The fact that politicians know this makes the selection process intensely political — but to admit it would make the Court a target for attack like any other political actor. And who then would decide the disputes? As a society, perhaps the standard we demand of the justice system is not impartial justice — it’s just open reason-giving in a form which we find satisfying.

That tension — between a demanding ideal of blind justice and an imperfect reality — drives the contorted politics of Supreme Court nominations. Most political players want to maintain the Court’s legitimacy in the eyes of the public. But knowing the principle which underpins its legitimacy is flawed — knowing there will be winners and losers — everyone wants events to break their way. The renowned American political scientist Robert Dahl described it best in 1957:

“As a political institution, the Court is highly unusual, not least because Americans are not quite willing to accept the fact that it is a political institution, and not quite capable of denying it; so that frequently we take both positions at once.”