In his address to Congress on March 6, President Bush asked for prompt action on a crime bill. He is getting some action in committee, but the regrettable fact is that some of the action is action in reverse. Parts of the omnibus bill now pending in the Senate would do more harm than good.

It needs to be remarked once more that any federal crime bill is largely and inevitably an act of minimal effectiveness. Of the thousands of violent offenses reported annually, no more than 5 percent are crimes against federal law. All the rest are governed by state law. This is exactly how the system should work. Lovers of federalism, one of the bedrock principles of our constitutional structure, should resist congressional attempts to muscle into state responsibilities by invoking the commerce clause.Both the Democrats' bill and the president's bill are curiously obsessed with aspects of capital punishment. One purpose is to extend the range of cases in which a death sentence may be imposed. Another objective is to limit the application of habeas corpus proceedings. A third purpose is to deter traffic in forbidden drugs.

These are respectable purposes, but their value is limited. For one example, attempts to assassinate a visiting head of state are likely to be extremely rare. It is highly doubtful that a political assassin will be deterred by the possibility of a death sentence. The provision is mostly braggadocio: Look how tough we are on crime!

Moreover, the impressive structure on capital punishment would be undermined by Sen. Edward Kennedy's "Racial Justice Act." He would write this bad idea into the omnibus bill. His purpose, in effect, is to add a quota requirement to the sentencing phase of capital cases.

As Attorney General Richard Thornburgh has observed, "The likely practical effect of the Racial Justice Act would be to invalidate all death sentences that are currently in effect in the United States, and to preclude all future use of the death penalty." This is because more blacks than whites, proportionately speaking, are sentenced to death. The statistical disparities are obvious; in any given case they also are meaningless.

No one knows whether capital punishment works. We never will know if the risk of being executed actually deters violent criminals. Maybe yes, maybe no. The truth is unknowable. But we do know that roughly one-half of all victims of murder and willful homicide are black. If Kennedy's abstract theories of racial justice should be adopted, the death penalty would not be available as either punishment or deterrence in these cases.

In another area, the judiciary committees will want to pray carefully over provisions to redefine the exclusionary rule. The rule requires that probative evidence be excluded at trial if the evidence has been acquired without meticulous attention to judge-made regulations under the Fourth Amendment.

Court observers will recall one weird case in which a police officer, properly on the scene of a crime, noticed a stereo set that in all probability had been stolen. Without troubling to get a search warrant, he picked up the set to check the serial number on the bottom. This was held to be an unconstitutional violation of the right to be protected against unreasonable searches, and the evidence was thrown out.

Such stupid rulings have led to the administration's proposal that evidence should be admitted if law enforcement officers act "in good faith." Trivial flaws in the wording of a warrant should not provide a means for defendants to wiggle out of a just determination of their guilt.

A common-sense revision of the exclusionary rule would be useful, but the revision will have to be done with scrupulous care. The Fourth Amendment is precious. In our zeal to convict the guilty, we must not give law enforcement officers unbridled power to violate civil rights.

It should be possible, given a measure of good will on both sides of the political aisle, to put together a workable bill. The foremost civil right of every citizen is clear. As Thornburgh said in recent testimony in the Senate, it is the right "to be free from fear in our homes and on our streets." Over most of the nation, that right has sadly deteriorated. To the limited extent that a federal law may help, Congress should act. Time's a-wasting.