It is too early to know the effect of Israel’s killing Monday of the leader of the terrorist group Hamas. Chances are excellent that they will not be good.

Just as the Bush administration has found with the capture of Iraqi dictator Saddam Hussein, capturing or killing someone who is thought to direct suicide bombings, air raids and other acts of violence does not mean those attacks will stop. If Ariel Sharon’s government believed that attacks on Israelis would be lessened by killing Hamas founder Sheikh Ahmed Yassin, they were ill advised.

There is already evidence that the air strike that killed Mr. Yassin and 15 others has only inflamed Palestinian militants. Hundreds of thousands of Palestinians turned out for the slain leader’s funeral and may vowed reprisal for the Israeli attack. Crude attacks have already been launched on Israeli territory.

For Americans, the most chilling comment about the killing came from a statement Hamas faxed to the Associated Press. In it, for the first time, the militant group tied Israel’s actions to its American backing. “The Zionists didn’t carry out their operation without getting the consent of the terrorist American Administration, and it must take responsibility for this crime.” The statement went on to say “all the Muslims of the world will be honored to join in on the retaliation for this crime.”

National Security Advisor Condoleezza Rice said Monday that American officials had no advance warning of and did not approve the Israeli attack. Such a distinction does not matter to Muslim groups that see America’s $3 billion in annual aid to Israel, one-third of total U.S. foreign aid, as support for the country’s policies and practices.

There are further lessons here for the United States as well as it steps up its efforts to capture Osama bin Laden, now believed to be hiding in Pakistan. Shutting down terrorist groups and networks is not as easy as capturing one person. As Newsweek reported in its March 22 issue, there have been more major terrorist acts since Sept. 11 and the launching of America’s war or terror than in the 30 months prior to the attacks on the World Trade Center and Pentagon. “I think we may have cut off Al Qaeda’s head, but the rest of the body is working fine and has spawned 10 smaller heads,” a former counterterrorism official in the Bush administration told the magazine. This means that even capturing Mr. bin Laden may be largely symbolic.

The war against terrorism should be fought vigorously, but merely killing or capturing a few leaders does not protect a nation. Instead, policies that encourage economic development and empower angry young men and women so that they no longer direct their hatred at the United States and its allies will be more effective in the end.