For those who think “courtroom” is just another word for “obfuscation,” it won’t be surprising that a new federal law on class-action lawsuits is being widely misrepresented by both sides in the long-lasting dispute.

President Bush signed the Class Action Fairness Act of 2005 on Friday, sharply curtailing the number of class-action lawsuits that can be filed in state courts. Except for relatively small cases or those in which significant percentages of the plaintiffs and defendants are in the same state, such cases will have to go to federal courts instead.

To Thomas Donohue, president of the U.S. Chamber of Commerce, that’s a stroke to “take back our civil justice system from plaintiffs’ lawyers seeking jackpot justice.”

But to Senate Democratic leader Harry Reid of Nevada, a former trial lawyer, “It is about hurting consumers and helping corporations avoid liability for misconduct.”

Even President Bush quietly acknowledges that class-action suits serve the interests of justice in certain situations, but in their louder pronouncements he and his allies convey a contemptuous attitude toward the entire court system. Which is what Reid and other critics of the class-action measure are doing, also without justification, toward its supporters.

Critics say, accurately, that federal courts certify fewer class-action suits than state courts. (For what it’s worth, a federal judge on Tuesday OK’d a class-action suit by United Airlines employees against trustees of the company’s employee stock ownership plan.) But the disparity between state and federal treatment isn’t a matter of politics as much as a matter of odds. Lawyers working on national cases have thousands of state courts to choose from in the search for an accommodating judge.

In the process, a handful of local jurisdictions have acquired reputations as especially friendly to class-action suits, giving rise to national decisions being rendered by local judges — judges in, say, Madison County, Illinois, whose rulings apply Illinois law to businesses and consumers in Maine, or Georgia, or Washington.

The Class Action Fairness Act supports the notion that state courts should handle predominantly state cases and federal courts should handle predominantly interstate cases. Among other corrective steps, it also deprives lawyers of lucrative financial rewards for brokering cases where consumers receive only token damages — video-rental coupons, for example.

The new legislation does not prevent class-action suits as a legitimate way to get justice for broad categories of plaintiffs injured by a common pattern of conduct. It just makes them more orderly.