Why did the Founders bother toiling in the summer heat of Philadelphia in 1787 writing a Constitution when they could have relied on the consciences of Supreme Court justices like Anthony Kennedy instead?

Kennedy is the Supreme Court's most important swing vote and its worst justice. Whatever else you think of them, a Justice Scalia or Ginsburg has a consistent judicial philosophy, while Kennedy expects the nation to bend to his moral whimsy. With apologies to Louis XIV, Kennedy might as well declare "la constitution, c'est moi!"

In a 2005 interview, Kennedy said of the court, "You know, in any given year, we may make more important decisions than the legislative branch does -- precluding foreign affairs, perhaps." (He was wise to include the "perhaps," in light of the recent Guantanamo Bay decision.) He went on to note how judges need "an understanding that you have an opportunity to shape the destiny of the country."

So much for the country's destiny being shaped by a free people acting through their representative institutions, within certain constraints it enshrines in the Constitution. That wouldn't allow nearly enough room for what Jeffrey Rosen, in a devastating profile of the justice in The New Republic, calls Kennedy's "self-dramatizing moralism."

On any politically charged case, we are supposed to wait with bated breath while the famously agonizing Kennedy decides which side he is going to bless with his coveted fifth vote. In so doing, Kennedy believes he is, in Rosen's description, creating "a national consensus about American values that will usher in what he calls 'the golden age of peace.'" Observers less besotted with Justice Kennedy than Justice Kennedy might put it differently: making it up as he goes along.

Two years ago, Kennedy joined the majority in the Hamdan v. Rumsfeld case that urged the president to obtain congressional approval for the system of military tribunals at Gitmo. President Bush did, but Kennedy wrote the 5-4 majority decision in this year's Boumediene v. Bush striking down the system anyway.

Kennedy quoted the World War II-era Eisentrager decision -- upholding the military trial of German detainees -- to show that there were greater practical difficulties back then with judicial interference in military detentions. He left unremarked that the Eisentrager decision unmistakably says -- a mere paragraph after his citation! -- that the Constitution does not apply extraterritorially: "No decision of this Court supports such a view. None of the learned commentators on our Constitution has ever hinted at it."

Indeed, Kennedy blew through some 200 years of precedent with nary a backward glance. Just another day at the Kennedy Court.

It should be no surprise how Kennedy construes the Eighth Amendment's prohibition of "cruel and unusual punishments." It is warrant for the court to exercise its "independent judgment" of "the evolving standards of decency that mark the progress of a maturing society," as Kennedy put it in this term's 5-4 Kennedy v. Louisiana decision forbidding capital punishment in cases of child rape.

The signature of a Kennedy opinion is vaporous moralizing, whatever side he comes down on. In the 1992 Casey decision upholding Roe v. Wade, he waxed poetic about "the right to define one's own concept of existence, of meaning, of the universe, and of the mystery of life." In the 2007 Carhart decision upholding the partial-birth abortion ban, he waxed again, this time about "respect for human life find[ing] an ultimate expression in the bond of love the mother has for her child."

Evidently, Kennedy goes about his job unburdened by the fact that his views on existence or on the mother-child bond have nothing whatsoever to do with the Constitution. But so it goes, as long as the Supreme Court is divided between four liberals, four conservatives and one self-important man who can't differentiate between his inner compass and the nation's fundamental law.

Kennedy fashions himself an instructor to the nation. And he is -- in the arbitrary ways of judicial lawlessness.