At both ends of the ideological spectrum, politicians, activists, journalists, and academics like to stress how big a change the next Supreme Court justice could make in the course of the law. The appointment will, says the conventional wisdom, be among President Obama’s most important legacies.

Many also stress how far to the right (say liberals) or left (say conservatives) of center the Supreme Court has been in recent years, the better to dramatize the need to correct the perceived imbalance.

And the dominant media image has been of "the conservative Court" (recent articles in The Washington Post), or "the Supreme Court’s conservative majority" (New York Times editorials), or a Court "as conservative as it’s been in nearly a century" (Newsweek commentary by my friend Dahlia Lithwick).

All this brings to mind three contrarian theses.

First, it simply won’t make much difference in the next five or so years — if ever — whom Obama picks from the lists of moderately liberal, extremely liberal, and just plain liberal candidates leaked by the White House.

Indeed, I can’t think of a single case or issue that would foreseeably be decided differently depending on whether the nominee turns out to be the most or the least liberal of those under serious consideration.

The Court is by nature quite stable. Imagine, for example, that Obama nominated and the Senate confirmed a person more liberal than either John Paul Stevens or any other current justice. No matter how passionate, or how brilliant, or how persuasive, he or she could move the law no further than at least four others were willing to go. And given the justices’ fierce independence, it’s hard to imagine any of them lurching leftward at the urging of the new kid on the block.

Editor’s Note: This is an updated version of Stuart Taylor’s Dec. 12 Opening Argument column.

What chances of success await the lawsuits challenging the constitutionality of the new health insurance reform law filed by 14 state attorneys general this week, with more lawsuits by states, individuals, and companies in the pipeline?

Not much, according to most of the academic experts who have weighed in. They confidently predict that the Supreme Court will (if the case gets that far) uphold the new law’s major provisions. These include the much-debated mandate for individuals to buy comprehensive health insurance unless they’re already covered by employer-based plans, and also the requirement that states spend billions of dollars expanding their Medicaid programs (unless they withdraw) and administering the complex new law.

These experts cite the justices’ very broad reading since the New Deal of Congress’ powers to regulate interstate commerce and to tax and spend.

The need to govern an ever more interconnected nation has spawned a long line of precedents expanding the commerce power.

I, too, would bet on the major provisions of the 2,400-page law being upheld. But "these challenges are not frivolous," as the Washington Post said in an editorial, and "the case is not as clear-cut as many legal scholars have argued."

The fact is that the costly federal mandates that the law imposes on state governments, individuals and families are without close precedents. And the lopsided academic response is attributable partly, though not entirely, to the lopsidedly liberal policy preferences of the professoriate.

Indeed, most scholars and other analysts have virtually ignored the new law’s most vulnerable (in my opinion) major provision, which the plaintiff states say violates their sovereignty.