The bumper-sticker liberal view of constitutional interpretation might begin with President Obama’s assertions that "the Constitution… is not a static but rather a living document and must be read in the context of an ever-changing world," and that "we need somebody who’s got the heart — the empathy — to recognize what it’s like to be a young teenage mom" or "to be poor or African-American or gay or disabled or old."

The bumper-sticker conservative view might begin with the standard denunciations of "legislating from the bench" and "judicial activism." Other formulations include: "Judges are like umpires. Umpires don’t make the rules; they apply them." "As a judge, I don’t make law…. I apply the law to facts." "Judges… don’t determine the law. Congress makes the laws. The job of a judge is to apply the law."

It’s notable that while the "umpire" analogy came from Bush nominee John Roberts in 2005, the subsequent two conservative-sounding quotes came from Obama nominee Sonia Sotomayor.

Sotomayor worked very hard last week not to sound like a liberal. So hard as to suggest that she and her White House handlers understand that the living-Constitution-plus-empathy approach is seen by many voters — fairly or unfairly — as a facade for judges rewriting the law to favor liberal constituencies and causes.

But the simplistic picture painted by many conservatives — and now by Sotomayor — of judging as a mechanical exercise with no place for moral and political values is unreal to anyone who understands the subjective nature of the choices that judges, and especially justices, must often make.

The Supreme Court would not split 5-4 on so many of the hardest questions if the answers could be discerned simply by applying the Constitution and other laws to the facts. The legal materials to be interpreted are sometimes so ambiguous or conflicting, and their meaning so debatable, that judges have no option but to "make law" by choosing among two or more equally plausible interpretations. And individual judges’ personal values and views of the world unavoidably help shape such choices.

Astute conservatives know this. "Conservative boilerplate" ignores the fact that "there is inevitably a great deal of ambiguity in the law," Heather Mac Donald writes in National Review Online. "’Original intent’ is a much more problematic concept than its acolytes admit. Language rarely produces single meanings. And yes, judges sometimes cannot avoid making ‘policy’ when they are called upon to extend statutes or precedents to unforeseen situations. The discourse about the law that conservatives routinely serve up in confirmation hearings is facile."

The starting point for honest constitutional analysis is the recognition that most of us — including most justices and legal scholars — care less about neutral principles of constitutional law than about the political results of the courts’ rulings on big issues such as abortion, race, and religion.

So who needs apolitical constitutional principles? The answer is that judicial review — the power invoked by unelected, life-tenured justices and judges to veto policies set by the elected branches — is tolerable in a democracy only if the judges are enforcing the higher law embodied by the Constitution, rather than their own subjective policy preferences.

But it has always been hard — and gets harder all the time — to reach consensus on how to interpret the 222-year-old document and its amendments, especially vague phrases such as "due process" and "equal protection." And constitutional principles are credible only if those who invoke them stick with them even when the results aren’t politically congenial.

The name of the game for many constitutional theorists, therefore, is to formulate principles that will lead to politically congenial results most of the time but are not transparently political.

Attacks on the Supreme Court for concocting bogus constitutional principles to usurp elected officials’ powers are almost as old as the Republic. Presidents including Jefferson, Lincoln and Franklin Roosevelt complained of what Roosevelt called the court’s efforts "to amend the Constitution by the arbitrary exercise of judicial power."

He was complaining about conservative justices striking down New Deal programs. But in the 1960s and thereafter, it was the more liberal justices who imposed their personal values on the nation — on issues such as abortion, the death penalty and criminal defendants’ rights — by striking down state and federal laws that had long been considered perfectly constitutional.

Leading the liberal reform offensive was the late, great Justice William Brennan. He saw the Constitution as "a sparkling vision of the supremacy of the human dignity of every individual" — a vision that he sometimes carried to the point of clashing with the Constitution’s specific text. Brennan also told clerks that "with five votes, you can do anything around here."

Brennan and his colleagues did what they wanted when they had five votes — and in the process angered many voters. That’s why Richard Nixon’s attacks on the court helped him win the 1968 election.

(I liked and admired Justice Brennan and personally favor the policy results of some of the decisions mentioned above. But I find them hard to reconcile with the Constitution.)

The conservative simplicities discussed above were devised as a political response to an accurate perception that liberals on the Warren and Burger Courts had gone beyond drawing upon their values to resolve ambiguities in the Constitution, and beyond applying it to new circumstances, and were instead changing the meaning of the constitutional language itself.

Conservatives including Robert Bork and Antonin Scalia mounted an intellectually muscular attack on such liberal jurisprudence, anchored in their views that the courts must adhere strictly to the "original intent" (Scalia prefers "original meaning") of the Constitution and its amendments. Originalists touted their approach as the only way to prevent judges from twisting vague constitutional language to reach results that would have horrified the framers.

Meanwhile, much of liberal constitutional thinking was devolving into what Mac Donald calls today’s "mad world of academic legal theory" and its "self-indulgent wallowing in narcissism."

Writes Mac Donald: "The claims that run through Sotomayor’s speeches on identity and the law — that… the white, male world of law suppresses the distinct ‘voices’ of minorities and women; that those ‘voices’ are ‘rich[er]’ and ‘better’ than those of white males — are utterly unremarkable within the legal academy. They form the core of feminist legal theory and ‘critical race studies.’… These twin theories reject the ideal of neutral legal analysis in favor of an uninhibited embrace of self-engrossed identity cultivation. Their practitioners produce law-review articles exploring how their… markers of racial or ethnic identity shaped their understanding of the law. They specialize in the manufacture and exploitation of pseudo-incidents of sexism and racism." Such teaching "forms part of the understanding of the law with which law schools imbue their students."

(For more detailed, and sympathetic, discussions of some of the liberal theories that Mac Donald pillories, see these books from the American Constitution Society. For more detailed conservative points, see this Federalist Society reading list and the book Scalia Dissents.)

Liberal experts have been as busy as conservatives like Mac Donald debunking the opposing camp’s approaches to constitutional law, including originalism. And Senate Democrats have used the Sotomayor confirmation process as an occasion to turn the old charge of "judicial activism" against conservatives including Chief Justice Roberts.

These conservatives, the liberal critics say, have been especially eager in recent decades to rewrite the Constitution to strike down federal and state policies including racial preferences, restrictions on campaign spending, and gun control.

More on that debate in my next post.