After the United States Supreme Court decided Bush v. Gore,  the case that ended the 2000 presidential election, the decision was said by many to epitomize the politics of law.  Specifically, it was said to show that the Rehnquist Court is group of ideologues primarily motivated by a hidden conservative political agenda rather than “neutrally interpreting” law. Or as leading empirical scholars of the Court, Jeffrey Segal and Harold Spaeth, said:
If [Bush v. Gore] tells us anything, it’s that the Supreme Court is more secure and more comfortable than it has ever been in pushing an agenda that is not only activist and conservative, but also blatantly partisan. 
These researches also told us that the election case was not a mere aberration; it was a difference only in size rather than kind. They write, “While Bush v. Gore may appear to be the most egregious example of judicial policy making, we suggest that it is only because of its recency.”  Other examples include: voting to weaken the Americans with Disabilities Act;  using the commerce clause to strike down the Violence Against Women Act;  declaring provisions of the “Brady Bill” unconstitutional;  voting against age discrimination claims  and workers seeking overtime;  and using the Tenth Amendment’s “sovereign immunity” doctrine to frustrate the pursuit of legal claims against state governments.  The authors then characterize the voting bloc that defines and empowers the Court’s hidden conservative agenda as “The Rehnquist Five,”  which are: Chief Justice William Rehnquist and justices Antonin Scalia, Sandra Day O’Connor, Anthony M. Kennedy and Clarence Thomas.
Three years later, however, the fashion of the commentary changed. In June of 2003 when the Court decided Lawrence v. Texas,  the decision protecting sodomy – and as well Grutter v. Bollinger,  the decision upholding affirmative action – newspaper stories now declared that the Court had turned to the left.  Or as two leading commentators remarked on the program A NewsHour with Jim Lehrer:
I think anyone who thinks this is a conservative court is smoking something ... because this court has done things which the Warren Court never dreamed of doing ... so I really don't think this is a conservative court at all, despite the fact that seven of the Justices had been appointed by Republicans, it's not the kind of court conservatives would want. 
-- John Yoo of the University of California-Berkeley
I would suggest that the court is really quite a moderate court or a centrist court, that in fact expresses a great deal of the values expressed elsewhere in society, rather than seeking to change those values. ... I would say that the big theme of the court is that it's a centrist, moderate court that expresses the values of most Americans. 
– Kathleen Sullivan, Dean of Stanford University Law School
Obviously, these characterizations are contradictory. The simple fact of the matter is that, sometimes, voting on the Court appears to fit a political stereotype, but other times it does not. Other recent examples where voting patterns seem less ideologically driven include the Court’s decision not to influence the partisan control the U.S. Senate in the 1992 midterm elections;  the decision granting due process rights to suspected terrorists captured in battle and held by the military outside United States borders;  the decision outlawing the death penalty for mentally-retarded murderers;  and the decisions declaring unconstitutional many sentencing-enhancement laws that were originally enacted to be “tough on crime.”  I should probably mention the Rehnquist Court’s infamous decisions protecting flag burning  and abortion,  even though they are now too old to be considered “recent.”
Why does this happen? What factors might cause conservative and liberal justices to vote as one “expects” for some cases but not others? Is it strategy? Is it fear of the other branches of government? Is it a larger concern for the integrity of legal text or doctrine? Legal philosopher and law professor Ronald Dworkin suggests that the reason why justices behave the way they do has something to do with the “gravitational force” of law.  Essentially, Dworkin’s point is that justices are influenced by important legal principles and moral standards – things that give weight or structure to decision making, but are not themselves determinative.  But Segal and Spaeth (and others) suggest that “principles” do not structure justices away from their biases; they only fortify them.  Interestingly, what hides beneath this debate is a dispute not so much about politics, but epistemology. One view sees the concept of legal justification as a force external to, and in competition with, the judicial will, while the other sees it as a toy or instrument of such a will.
In this work, I help explain why voting on the Court appears politically stereotypical in some cases but not others. In doing this, I also show that the Dworkin view of legal justification seems to be a more accurate description of how justices tend to behave than Segal and Spaeth’s view.  What I show in this work is a simple, yet profound, notion: law matters. More specifically, I show that the legal words of the Constitution do, indeed, affect how justices decide cases. The way that legal language is shown to structure decision making is through a concept I refer to as “language rigidity.” Rigidity is simply the idea of how clear the words of a sentence are. Some sentences are more precise in meaning than others. My work develops a criteria for placing the meaning of certain sentences in the Constitution in an ordinal level of rank according to their clarity. I then use a logistic regression analysis to show that language rigidity effects voting on the Court.
My central theory is that “value voting” – voting one’s political ideology – is much harder for justices to do when the words of the Constitution or statute being interpreted do not seem to allow it. But when the words of a legal command are vague and indeterminate, I expect value voting to be more widespread. I refer to this theory as the “rigidity hypothesis.” By validating it, I demonstrate that law is a force that structures and even tempers the political bias of justices. Quite simply, when the words of law are stern and clear, political stereotypes fail to describe judicial behavior very well. But when law is “absent” – when its words are poetic and vague – the critique of a political court seems much more accurate.
Although the validation of the rigidity hypothesis is itself important, its corollary may be an equally remarkable contribution to the judicial-politics literature. That is, in proving that law matters, I also prove something that is necessarily related: the force of political ideology on the Court is fluctuating rather than defining. This finding is important because the current empirical research in political science seems to misunderstand it. My work shows, for example, that political ideology seems to be a force that dominates some areas of Court voting – e.g., search-and-seizure and obscenity cases – but not other areas (e.g, core political speech). I like to describe this revelation with the metaphor of ocean tides. For some controversies, the Court experiences high political tide; for others, the political tide is low.
. 531 U.S. 98 (2000).
. See e.g., Alan M. Dershowitz, Supreme Injustice: How the High Court Hijacked Election 2000 (Oxford University Press, 2001); Cass Sunstein,“What We'll Remember in 2050: 9 Views on Bush v. Gore,” The Chronicle of Higher Education, B15, January 5, 2001; Bruce Ackerman, “The Court Packs Itself," The American Prospect, vol. 12 no. 3, February 12, 2001; Ronald Dworkin, “A Badly Flawed Election,” New York Review of Books, vol. 48, no. 1, Jan. 11, 2001.
. Jeffrey A. Segal and Harold J. Spaeth, The Supreme Court and the Attitudinal Model Revisited (New York: Cambridge University Press, 2002), 431.
. Board of Trustees v. Garrett, 531 U.S. 356 (2001).
. United States v. Morrison, 529 U.S. 598 (2000).
. Printz v. United States, 521 U.S. 848 (1997).
. Kimel v. Florida Board of Regents, 528 U.S. 62 (2000).
. Alden v. Maine, 527 U.S. 706 (1999).
.See, Seminole Tribe v. Florida, 517 U.S. 44 (1996); City of Boerne v. Flores,526 U.S. 507 (1997); and Florida Prepaid v. College Savings Bank, 527 U.S. 627 (1999).
. Segal and Spaeth, The Attitudinal Model Revisited, 35-36.
. 123 S. Ct. 2472 (2003).
. 539 U.S. 306 (2004).
. See, e.g, Anne Gearan and Associated Press,“Conservative High Court Leans Left; Justices do About-Face on Gay Rights Issues, Affirmative Action Policy,” The Detroit News, June 29, 2003, (“In blockbuster rulings on affirmative action and gay rights and in less heralded decisions this term, a Supreme Court dominated by conservative jurists looked less conservative than it has in years.”).
. “Online NewsHour: Supreme Court Wrap, June 27, 2003,” Public Broadcasting Service, http://www.pbs.org/newshour/bb/law/jan‑june03/scwrap_06‑27‑03.html (accessed on June 18, 2004).
. Forrester v. New Jersey Democratic Party, 6123 S. Ct. 673 (2002).
. Hamdi v. Rumsfeld, 124 S. Ct. 2633 (2004) .
. Atkins v. Virginia, 536 U.S. 304 (2003).
. Apprendi v. New Jersey, 530 U.S. 466, 498-499 (2000);Ring v. Arizona, 536 U.S. 584 (2002); Blakely v. Washington, No. 2004 U.S. LEXIS 4573.
. Texas v. Johnson, 418 U.S. 405 (1989).
. Planned Parenthood v. Casey, 505 U.S. 833 (1992).
. Ronald Dworkin, Taking Rights Seriously (Duckworth & Company, 1977), 113; and Law's Empire, (Cambridge: Harvard University Press, 1986), 239.
. See Ronald M. Dworkin, “The Model of Rules,” in Philosophy of Law, Sixth Edition (Wadsworth, 2000), edited by Joel Feinberg and Jules Coleman, 140.
. Segal and Spaeth, The Attitudinal Model Revisited,. 86, 432-433.
. I do not mean the glorified view that all justices are Herculean figures. “Hercules” was Dworkin’s hypothetically-perfect jurist. I mean the empirical claim: that legal text and doctrine effects judicial behavior independently of judicial politics. I will capture this effect empirically so that it can no longer be thought of by skeptics as a kind of popular mythology.