THE REPORTS OUT of northern Mali are more appalling by the day. A vast, arid swath of Africa has fallen under the control of radical Islamists who are imposing a strict form of sharia and building a new stronghold for al-Qaeda in the Islamic Maghreb. As punishment for robbery, the Islamists have hacked off people’s hands and feet. A man told the Economist that the top of his ear was sliced off for smoking. “For drinking, they cut off your head,” he said.

The radical Islamists have also destroyed ancient landmarks in the north and become entrenched in an area larger than France or Texas. Two groups affiliated with al-Qaeda have carved it up among themselves, controlling Timbuktu and Gao. What they will do with this prize is anyone’s guess, but it seems likely to become a bastion for extremists to train and thrive with impunity.

There has been no shortage of alarms. “We have to act as quickly as possible,” France’s ambassador to the United Nations, Gerard Araud, said Thursday. Secretary of State Hillary Rodham Clinton said last month, “We all know too well what is happening in Mali, and the incredible danger posed by violent extremists imposing their brutal ideology, committing human rights abuses, destroying irreplaceable cultural heritage.” She called Mali “a powder keg that the international community cannot afford to ignore.”

But the international community is once again slow to act. Granted, the central government in the capital, Bamako, is weak and disorganized. The democratically elected government was overthrown in March, followed by seizure of the north by ethnic Tuareg rebels, who were then rapidly displaced by the Islamists. The Economic Community of West African States (ECOWAS)has asked the Security Council to authorize military intervention to oust the Islamists, but so far the council has demanded more details. Gen. Carter F. Ham, commander of the U.S. Africa Command, said last month that “the one course of action that we are not considering is U.S. boots on the ground in Mali.”

Short of boots on the ground, however, more can and should be done. The collapse of landlocked Mali into another unhinged, failed state will threaten the region. The country must resolve ethnic grievances, hold elections, and reestablish the defense and security forces. But that is a tall order that takes time. The United States has called for appointment of a special U.N. envoy and creation of a diplomatic core group. France is circulating a draft U.N. resolution that would step up pressure on Mali and its African neighbors to agree quickly on a workable military plan. Eventually, the use of force will probably be necessary, but any ECOWAS intervention will need U.N. backing and support.

Talk of a powder keg needs to be translated into concrete moves before Mali becomes a new Somalia or Afghanistan.