General James Jones, President-elect Obama’s choice as national-security adviser, said earlier this week that a more “comprehensive” strategy was needed to defeat the Taliban and al-Qaeda in Afghanistan. Part of his comprehensive approach would be to intensify the campaign against the illegal drug trade. That would be a disastrous mistake. The opium trade is such a huge part of Afghanistan’s economy, that efforts to eradicate it would alienate millions of Afghans and play into the hands of the terrorists.

Under pressure from Washington, President Hamid Karzai has already called on the Afghan people to wage war against narcotics with the same determination and ferocity that they resisted the Soviet occupation in the 1980s. Given the economic and social realities in Afghanistan, that is an unrealistic and potentially very dangerous objective.

Despite the comments of General Jones, there has long been skepticism in U.S. and NATO military circles about the wisdom of pursuing a vigorous war on drugs in Afghanistan. Commanders correctly believe that such an effort complicates their primary mission: eradicating al-Qaeda and Taliban forces.

There is little doubt that al-Qaeda and other anti-government elements profit from the drug trade. What drug warriors refuse to acknowledge is that the connection between drug trafficking and terrorism is a direct result of making drugs illegal, thereby creating an enormous black-market premium. Not surprisingly, terrorist groups in Afghanistan and other countries are quick to exploit such a vast source of potential funding. Absent a worldwide prohibitionist policy, the profit margins in drug trafficking would be a tiny fraction of their current levels, and terrorist groups would have to seek other sources of revenue.

In any case, the United States faces a dilemma if it conducts a vigorous drug-eradication campaign in Afghanistan in an effort to dry up the funds flowing to al-Qaeda and the Taliban. Those are not the only factions involved in drug trafficking. Evidence has emerged that officials in Karzai’s government, perhaps even the president’s brother, are also recipients of largesse from the narcotics trade. Even more important, many of Karzai’s political allies are warlords who control the drug commerce in their respective regions. They use the resulting revenues to pay the militias that keep them in power in their fiefdoms and give them national political clout. Some of these individuals backed the Taliban when that faction was in power, switching sides only when the United States launched its military offensive in Afghanistan in October 2001. Antidrug campaigns might cause them to change their allegiance yet again.

In addition to the need to placate cooperative warlords, the U.S.-led coalition relies on poppy growers as spies for information on movements of Taliban and al-Qaeda units. Disrupting the opium crop alienates those vital sources of information.

The drug trade is a crucial part of Afghanistan’s economy. Afghanistan accounts for more than 90 percent of the world’s opium supply, and opium poppies are now grown in most provinces. The trade is roughly one-third of the country’s entire gross domestic product. According to the United Nations, some five hundred nine thousand Afghan families are involved in opium poppy cultivation. Even measured on a nuclear-family basis, that translates into about 14 percent of Afghanistan’s population. Given the role of extended families and clans in Afghan society, the number of people affected is much greater than that. Indeed, it is likely that at least 35 percent of the population is involved directly or indirectly in the drug trade. For many of those people, opium poppy crops and other aspects of drug commerce are the difference between modest prosperity (by Afghan standards) and destitution. They do not look kindly on efforts to destroy their livelihood.

Despite those daunting economic factors, the Bush administration has put increased pressure on the Karzai government to crack down on the drug trade, and the incoming Obama administration apparently intends to continue that strategy. The Afghan regime is responding cautiously, trying to convince Washington that it is serious about dealing with the problem without launching a full-blown antidrug crusade that will alienate large segments of the population. It has tried to achieve that balance by focusing on high-profile raids against drug-processing labs—mostly those that are not controlled by warlords friendly to the Kabul government. Afghan officials have been especially adamant in opposing the aerial spraying of poppy fields—a strategy that Washington has successfully pushed allied governments in Colombia and other South American drug-source countries to do.

Washington’s pressure on Karzai is myopic. The Taliban and their al-Qaeda allies are rapidly regaining strength, especially in Helmand and Kandahar provinces, perhaps not coincidentally the areas of the most vigorous antidrug campaigns. If zealous American drug warriors alienate hundreds of thousands of Afghan farmers, the Karzai government’s hold on power could become even more precarious. Washington would then face the unpalatable choice of risking the reemergence of chaos in Afghanistan, including the prospect that radical Islamists might regain power, or sending more U.S. troops to stabilize the situation beyond the reinforcements already contemplated for 2009.

U.S. officials need to keep their priorities straight. Our mortal enemy is al-Qaeda and the Taliban regime that made Afghanistan into a sanctuary for that terrorist organization. The drug war is a dangerous distraction in the campaign to destroy those forces. Recognizing that security considerations sometimes trump other objectives would hardly be an unprecedented move by Washington. U.S. agencies quietly ignored drug-trafficking activities of anticommunist factions in Central America during the 1980s when the primary goal was to keep those countries out of the Soviet orbit. In the early 1990s, the United States also eased its pressure on Peru’s government regarding the drug-eradication issue when President Alberto Fujimori concluded that a higher priority had to be given to winning coca farmers away from the Maoist Shining Path guerrilla movement.

The Obama administration should adopt a similar pragmatic policy in Afghanistan and look the other way regarding the drug-trafficking activities of friendly warlords. And above all, the U.S. military must not become the enemy of Afghan farmers whose livelihood depends on opium-poppy cultivation. True, some of the funds from the drug trade will find their way into the coffers of the Taliban and al-Qaeda. That is an inevitable side effect of a global prohibitionist policy that creates such an enormous profit from illegal drugs. But alienating pro-Western Afghan factions in an effort to disrupt the flow of revenue to the Islamic radicals is too high a price to pay. General Jones should reconsider his views.