With the justified firing of Gen. Stanley McChrystal and his replacement with Iraq water-walker David Petraeus, it’s as if people are hoping for a second coming of Jesus in Afghanistan. Unfortunately, the replacement may be similar to the second coming of the water-walking Joe Gibbs as coach of the Washington Redskins.

Although McChrystal’s derisive comments about high-level Obama administration officials weren’t as bad as Gen. Douglas MacArthur’s attempts to undermine President Harry Truman’s effort to keep the Korean War from turning into a nuclear war against China, such insubordination by a military officer toward the civilian command structure cannot be tolerated in a republic. If it is, the country may not be a republic for long. Thus, even many Republicans didn’t squawk about McChrystal’s sacking.

They, and almost everyone else in Washington, were comforted, even elated, that Gen. David Petraeus, the hero of the Iraq war, was recycled to command U.S. and NATO forces in Afghanistan. Everyone is hoping for a replay of the reductions in violence in Iraq.

Of course, Petraeus is partially responsible for that reduction in that violence, but not for the reasons commonly believed. The conventional wisdom is that Petraeus’ anti-guerrilla warfare strategy—winning the hearts and minds of the local population instead of blasting the insurgents to smithereens and also killing many civilians (this strategy is now being transplanted to Afghanistan)—was the cause of increased stability in Iraq. In fact, paying the Iraqi Sunni insurgents to fight al-Qaeda instead of U.S. forces and prior ethnic cleansing that separated the warring Sunni and Shi’ite groups were the main factors leading to the reduction in violence in Iraq, according to many counterinsurgency experts. Petraeus’ short-term bribery will probably not even hold in Iraq. The real problem is the ethno-sectarian fissures that will likely reignite once the United States leaves. By funding and arming the Sunnis, as well as Iraqi Shi’ites and Kurds, Petraeus, to achieve short-term gains in stability, may end up inadvertently worsening post-U.S. ethno-sectarian warfare.

Even if we accept the dubious propositions that Iraq’s worst days are behind it and that Petraeus’ counterinsurgency strategy was primarily responsible for the reduction of violence, the skeptical media keeps asking the question of whether it can be transplanted to Afghanistan. After all, even many U.S. troops complain that their casualties are going up because they are not allowed to take the fight to the enemy, thus endangering civilians and ruining the “hearts and minds” strategy. The counterinsurgency strategy has been adopted to such an extent that the United States even announces offensives in advance, hoping that both the Taliban and civilians will flee the area.

American troops are right that there is a tradeoff between U.S. casualties and local civilian casualties; when civilian casualties are reduced, the U.S. military takes more of them, and vice versa. The two most important “centers of gravity” in any anti-guerrilla war are civilian opinion in the occupied nation and public opinion back home for the occupier. But to win local popularity, the U.S. military must incur higher casualties—as is now occurring—which leads to erosion of support for the war back home. Predictably, a majority of Americans have soured on the Afghan war after nine years of quagmire.

Despite taking higher casualties, however, the United States doesn’t seem to be winning many Afghan hearts and minds either. Counterinsurgency campaigns are rarely effective for several reasons, the principal one being that it is difficult to get around being regarded as a foreign occupier. In Afghanistan, even the brutal Taliban has much support in the Pashtun community—the tribes that historically have been dominant in the country—because the group is regarded as a defender of the tribes against the Afghan government, which is perceived to be controlled by Uzbeks and Tajiks.

Other problems that foreign occupiers face include the fact that counterinsurgency is much more expensive to conduct than insurgency, foreigners usually have difficulty understanding the local culture, locals know that the foreigners will eventually leave and they will have to deal with the local insurgents, government organizations specializing in combat are ill-suited to the difficult task of nation-building, and nimble non-bureaucratic guerrillas can adapt faster to changes in the battlefield than the governments of the host nation and foreign occupier.

Thus, the second coming of Petraeus may instead resemble the return of storied coach Joe Gibbs to the Washington Redskins. Although he had been in four Super Bowls during his first tenure as coach, his resurrection fizzled because the NFL he returned to was not the same one he left. For Petraeus, Afghanistan is not Iraq.