As it becomes clear that President Barack H. Obama’s veto power and the Democratic majority in the Senate will prevent the Republican leadership in the House from achieving many of its goals for this Congress, the party is increasingly looking to another avenue to get its agenda through: the courts.

Republican state attorneys general have filed numerous lawsuits challenging the constitutionality of health care reform, with one Republican judge ruling the bill’s mandate for universal coverage unconstitutional and another one set to follow. New House energy chairman Fred Upton is pinning his hopes for undermining the Environmental Protection Agency’s new set of climate change regulations on the courts, urging the Environmental Protection Agency to wait until the issue makes its way through the courts for the rules to take effect. The House majority has even adopted rules requiring legislation to provide textual support from the Constitution—with the implicit assumption being that liberal policy goals are not authorized by the document.

All of this is dependent on the idea that there is a single correct interpretation of the Constitution that exists independently of the preferences of the current justices of the Supreme Court. This view is hardly limited to conservatives. The liberal legal philosopher Ronald M. Dworkin ’53 has defended this account of the law, arguing that a hypothetical “Judge Hercules,” with complete understanding of all the facts of a case and all the time necessary to mull them over, will arrive at a correct answer.

But, as first noted by those in the legal realism movement that cropped up at Harvard in the early 20th century, this view is badly misguided. For a bill to be constitutional does not mean that it conforms to some one true interpretation of the document. “Constitutional” instead means whatever five members of the Supreme Court want it to mean. Given the current composition of the court, it more specifically means whatever Anthony Kennedy wants it to mean.

On a certain level, this is obvious. The Supreme Court is, in practice, the branch of American government that can issue opinions on the Constitution that bind other branches. Those opinions need not in principle follow from a “correct” interpretation of the Constitution. Harvard law professor Mark V. Tushnet ’67 once memorably wrote that, if he were on the court, he would rule in ways that “advance the cause of socialism,” and then justify these rulings through more widely accepted legal language. There is no mechanism preventing justices from taking their own political preferences, cloaking them in ostensibly apolitical legal arguments, and then issuing the result as the opinion of the court.

Of course, it is possible that, even given this possibility, members of the judiciary do not in fact rule this cynically. But there is significant empirical evidence to suggest that partisan affiliation has a lot to do with federal judges’ rulings on controversial issues.  A new movement in legal academia, dubbed the “New Legal Realism,” has used modern quantitative tools to analyze federal court decisions, and found that the political affiliation of judges has a large effect on their jurisprudence. According to one analysis, Democratic appointees take a stereotypically liberal stance in 52 percent of cases, whereas Republicans take one in 40 percent, a significant difference.

What’s more, in three-person federal appeals court panels, the party composition of the panel itself has a strong influence. Panels composed of all Democratic appointees are significantly more likely to arrive at liberal decisions than those with two Democrats and a Republican, and vice versa. But in cases of abortion and capital punishment, judges tend to vote the party line regardless of the panel’s composition. In the most controversial of cases, then, fellow judges cannot even serve as moderating influences.

These findings hold up in the Supreme Court as well. The political scientists Jeffrey Segal and Harold Spaeth’s “attitudinal model” of Supreme Court decision-making argues that the justices’ attitudes–their ideological views, preferences, and so forth–are the most important factor in determining court outcomes. The model is over twenty years old, but has held up consistently to empirical analysis. Indeed, it has shown that attitudes have become even more important in recent decades.

The Supreme Court will ultimately decide which of Obama’s policies are constitutional based on their attitudes, not some objectively correct interpretation of the law. A more useful debate, then, will focus on whether having an unelected institution making decisions based on its personal preferences is desirable.

One answer, notably embraced by Tushnet in recent years, is to reject the Court’s power of judicial review as undemocratic. This view has some practical appeal to liberals who recall the early 20th century court’s resistance to economic regulation, and worry about the current Roberts court’s consistent pro-business bias. But since the 1950s, the Court has also provided assistance for liberal efforts on individual rights, from equal rights for racial minorities, women, and LGBT citizens, to a robust right to privacy. Most Western European countries, as well as Canada, have done without a similar judicial review system, but this has allowed for unconscionable policies, such as “hate speech” statutes and public surveillance systems, at which many Americans rightly recoil.

But ultimately, this is a question of politics. Where one stands on Constitutional interpretation, and the role of courts in deciding it, depends much more on one’s personal political preferences than on some objective account of what the document means.

Dylan R. Matthews ’12, a Crimson editorial writer, is currently studying abroad at Cambridge University.