A United Nations conference last weekend approved a historic agreement to fight global trafficking in small arms. Despite years of preparation, agreement hinged on last-minute negotiations, largely to meet U.S. objections. Fortunately, delegates understood the magnitude of the problem and put progress ahead of principle. An intermediate step has been taken to help rid the world of the scourge of small arms. Now governments must back the U.N. plan with action; enforcement of its terms will determine its success or failure.

In simplest terms, a small arm is a weapon that can be fired, maintained and transported by a single person. Also included in this category are light weapons, which can be carried by a pack animal or small vehicle. In other words, the terms cover all weapons from pistols to shoulder-fired antiaircraft missiles. It is estimated that there are 500 million such weapons around the world -- one for every 12th resident of the planet -- and they have become the weapons of choice because they are cheap and easy to use. Small arms were used in 46 of the 49 armed conflicts that were fought during the 1990s. Between 40 and 60 percent of these weapons are obtained illegally; the business is worth around $1 billion each year.

Since 1990, those weapons have claimed more than 4 million lives, the overwhelming majority of the victims - some 80 percent - are women and children. Millions more have been wounded, and over 14 million people have been uprooted in these conflicts. They have been forced to become refugees, and a potential source of instability in the countries to which they seek shelter. The use of small arms allows children to become soldiers; the psychological and social damage done by exposing children to war is incalculable.

The world cannot plead ignorance of the problem. Governments have complained about the growing flood of small arms that has been unleashed since the end of the Cold War, when the collapse of the Soviet Union marked the end of superpower concern about dampening conflicts and left small countries to the mercy of the market. Nearly 75 percent of U.N. members have developed measures in one form or another to deal with the problem. Unfortunately, many of the hardest hit countries, such as those in Africa, are just too big and the governments too poorly organized to stem the import of these weapons. There have been successful programs to disarm individuals and destroy weapons after peace has been restored, but by then, much damage has already been done. Regional organizations have tried to step in, but many of the combatants -- and suppliers -- are not among their members and that has limited the effectiveness of their measures.

The U.N. has tried to fill the gap. The General Assembly first voted to convene an international conference on the topic in 1998. In the Millennium Declaration of September 2000, members pledged to "take concerted action to end illicit traffic in small arms and light weapons, especially by making arms transfers more transparent and supporting regional disarmament measures." The delegates labored away for two years to prepare a draft for the most recent meeting, but U.S. objections, announced as soon as the conference began earlier this month, nearly scuttled an agreement.

The U.S. has two concerns. First, it opposes restrictions on the right of governments to support rebel groups. Proving again that "one man's terrorist is another man's freedom fighter," Washington wants to be able to help movements that fight governments the U.S. considers threatening: Resistance groups in Iraq are one example of this type of group. Second, in keeping with the National Rifle Association's interpretation of the U.S. Constitution, the U.S. will not countenance any restriction on the right of private citizens to own weapons. American delegates dismissed arguments that an international agreement of this sort would have no effect on U.S. domestic laws.

The result is a document that has been stripped of many of its most ambitious provisions. It is not a legally binding document. Member states have to go to their governments to pass measures to bring it into force. In one important concession, the U.S. did agree to a followup conference no later than 2006. That heartened some delegates, who envisioned this meeting as a step along the way rather than the culmination of the process, and leaves room for more biting measures in the future.

Perhaps then there will be a government in the U.S. that is not as beholden to the gun lobby. Unfortunately, while U.S. views may change, the number of victims of small arms and light weapons is sure to increase. Only a global initiative can halt the carnage. The U.S. is once again out of step with the rest of international society.