SOME OF THE MOST efficient firearms sought by terrorists -- international as well as domestic -- may flood the markets of this country if Congress fails to renew a federal ban on semiautomatic assault-style weapons. The ban is scheduled to expire next year after a decade in force; House Majority Leader Tom DeLay (R-Tex.) announced at one point recently that the House would not even have a vote on the matter. But House Speaker J. Dennis Hastert (R-Ill.) then insisted that no final decision had been made, noting that he first wants to talk to President Bush, who has been on record as supporting the ban. That's the right position, but it will take more than presidential lip service to uphold it in an election year.

The 1994 law made it illegal to manufacture, transfer or possess 19 specific models of semiautomatic weapons. It also banned ammunition magazines that hold more than 10 rounds. If anything, the law needs to be strengthened. A Congressional Research Service report released last week found that U.S. gun laws in general can be easily exploited by terrorist operatives shopping for weapons in this country. In the case of assault weapons, the gun industry has found clever ways to make cosmetic design changes in their models to get around the federal ban. Even so, according to the Brady Center to Prevent Gun Violence, every major law enforcement organization in the country has supported the ban. These groups point out that these firearms remain the weapons of choice for drug traffickers, gangs and paramilitary groups. As weak as the ban may be, evidence exists that the number of assault weapons traced to crimes dips when such laws are in place. In Maryland, for example, a ban on assault pistols took effect in June 1994. The Brady Center found that the number of these guns recovered by Baltimore police in the first six months of 1995 was down 45 percent from the comparable period the year before.

The ban on assault weapons needs time and broadening to have more effect. Reopening the gates to still more assault weapons makes no sense in civilized society. Congress and the president ought not make it any easier for terrorists, deranged people, drive-by shooters or criminals -- foreign or domestic -- to kill and maim.