When U.S. government officials and foreign policy pundits discuss terrorism, they usually focus on the characteristics, personnel, history, tactics, targets, objectives and effects of terrorist organizations. They rarely talk about motives.

To fully understand Islamic terrorism, one needs to understand what triggers this extraordinary rage. And throughout history one factor stands out above all else: the occupation of Muslim land by non-Muslim forces.

From the time of the Crusades, the pattern has been consistent. The Soviet Union learned this difficult lesson following its invasion and occupation of Afghanistan in the late 1970s. The Russians learned it again when they occupied Chechnya in the 1990s. Israel’s occupation of the West Bank and Gaza after the 1967 Six Day War and its military interventions in Lebanon triggered similar reactions, as did the U.S. military presence in Lebanon in the early 1980s. Indeed, it’s fair to say that Israel’s very existence—a non-Islamic state in land claimed by the Muslims—is part of the same pattern, as is the U.S. occupation of Iraq and Afghanistan.

There is much the United States could do to defuse the problem, and a good place to start would be by removing land-based U.S. forces from the Persian Gulf.

Even Osama bin Laden claims he attacks the United States primarily because of its military presence in the region. Other reasons, he claims, are secondary.

Remember, bin Laden first went to war not against the United States, but against the Soviets in Afghanistan. When he returned to his Saudi Arabia homeland after fighting the Soviets, he found a large--and to him unacceptable--U.S. military presence in the desert kingdom, which remained after evicting Saddam Hussein from Kuwait. It was then that the United States became a target.

During the Cold War, one could make a plausible argument for some U.S. involvement overseas to counter the expansionist Soviet superpower. When the Soviet Union collapsed, that rationale disappeared.

Even if the United States believes the global oil market will fail to deliver Persian Gulf oil to U.S. shores without U.S. military forces protecting it (a dubious proposition), the U.S. military could protect our oil lifeline from offshore, without troops stationed in Muslim countries.

The United States has done so before. In 1991, when the George H.W. Bush administration believed U.S. oil supplies were endangered by Saddam Hussein’s invasion of Kuwait, U.S.-based land and air forces were sent to the Gulf to push Saddam out of Kuwait. After the job was done, those forces should have been brought home. Instead, the United States established a large military footprint in the region, which, in retrospect, was exactly the wrong move.

Now it’s time to get rid of that unneeded land presence, not to increase the ante by talking about permanent U.S. bases in Iraq.

Just look at the troubles the United States has caused in Afghanistan. There, the continued U.S. occupation—which has changed its main focus from killing or capturing bin Laden to nation-building, counterinsurgency, and drug interdiction—is fueling a resurgence of the Taliban movement.

Only by minimizing the permanent U.S. military presence in Arab and Islamic lands can we hope to stem anti-U.S. terrorism. The United States should withdraw its forces from Afghanistan, inform the Afghans that U.S. forces will return if any Afghan government harbors al Qaeda, and use Special Forces to hunt down al Qaeda’s leadership. This process needs to be repeated in Iraq and the Persian Gulf.

The lesson learned is that empire does not enhance security--it undermines it. U.S. power on Islamic soil is especially problematical.