President Barack Obama knows the Afghan war is going badly, but he insists that the specter of an al-Qaeda comeback makes Afghanistan a “war of necessity”. So he has ordered some 30,000 new troops to the front, hoping to hold the line enough that Afghan forces can be built up to eventually take over the mission from the U.S. It may sound like a limited goal after the sweeping visions of democracy promised during the Bush years. But even that relatively modest strategy is based on some very questionable assumptions. Here are five of them: The Qaeda Threat Requires a Ground War Obama made the threat of al-Qaeda returning on the back of a Taliban victory the primary rationale for escalating the war in Afghanistan. But, as many have pointed out, al-Qaeda doesn’t need sanctuaries in order to plot terror attacks, and its leadership core is based in the neighboring tribal areas of Pakistan. Which means that 100,000 U.S. troops are now being committed to a mission whose goal is to prevent a few hundred men from re-establishing a base of operations. And then there’s the problem that having masses of U.S. troops in Afghanistan, for whatever reason, inevitably creates a nationalist backlash that fuels the insurgency — a problem that even Defense Secretary Robert Gates had noted early in the debate. The fact that the Taliban is now in effective control of as much as half the country eight years after being routed by the U.S.-led invasion is a sign that the local population is at least more tolerant of an insurgency against foreign forces. Expanding the ground war may not solve this problem. As University of Michigan historian Juan Cole wrote Wednesday, “The U.S. counter-insurgency plan assumes that Pashtun villagers dislike and fear the Taliban, and just need to be protected from them so as to stop the politics of intimidation. But what if the villagers are cousins of the Taliban and would rather support their clansmen than white Christian foreigners?” (See pictures of the battle against the Taliban.) Afghan Security Forces Can Be Trained to Take Over the Mission The centerpiece of Obama’s exit strategy is the training of Afghan security forces to take responsibility for fighting the Taliban, just as Iraqi forces have taken charge of security in Iraq. But Afghanistan is nothing like Iraq, and training may not be the decisive issue: Despite the U.S. having officially trained 94,000 Afghan soldiers, there’s no sign of an effective Afghan security force capable of fighting the Taliban. Desertion rates are high — one in four soldiers trained last year, by some accounts. So are rates of drug addiction. Most importantly, the most effective elements of the military are dominated by ethnic Tajiks, which does little to help win support of the Pashtuns, the country’s largest ethnic group and the one among which the insurgency is based. Unlike Iraq, Afghanistan had no powerful army or strong state before the U.S. went in — nor does it have the oil wealth that allows Iraq to pay for its own armed forces. And then there’s the question of whether they’ll be willing to fight the Taliban on behalf of a foreign-backed government.