CHARLESTON, W.Va. -- Part of the Islamic world went berserk because a crude, amateurish, low-budget movie defaming the Prophet Muhammad was made in America.

Screaming protesters filled streets in various Muslim nations. Cars burned. Rocks flew. Windows shattered. A U.S. ambassador and three aides were killed in Libya. More than a dozen rioters died in various clashes with police.

The widespread upheaval seems childish, brutal, infantile, uncivilized. This behavior raises serious doubt whether some Muslim societies are stable enough or mature enough for democracy.

Ominously, killing of American troops in Afghanistan by supposed Afghan "allies" worsened during the movie mayhem. On Sunday, an Afghan policeman killed four Americans in the southern city of Zabul. A day earlier, an Afghan militia member killed two Britons.

So far this year, 51 NATO soldiers in Afghanistan have been murdered in such "insider attacks." Some Muslims being trained to keep the mountainous Asian country safe after 2014's U.S. pullout evidently feel a suicidal urge to shoot "infidels" who occupy their nation. The killers usually die from return fire.

Because Americans in Afghanistan can't trust their "partners," the Pentagon is taking extreme steps to protect U.S. soldiers. Joint patrols with Afghan troops are being halted. Americans are ordered to carry loaded weapons at all times. Some U.S. soldiers are assigned to be "guardian angels" watching over Americans as they sleep.

All this ugliness, we think, is proof that America should end the Afghan occupation now, instead of waiting until 2014. What's the point of continuing to sacrifice American lives for a nation where mobs scream "Death to America" and "friendly" allies shoot Americans in the back?

Supposedly, the White House is delaying the U.S. withdrawal because it fears that Muslim terrorists will seize Afghanistan when American firepower is gone. Well, that risk will remain after next year's pullout. If the Muslim country is unfit for democracy now, we doubt that another year of U.S. military intrusion will make much difference.

American taxpayers are sinking billions into nation-building attempts in various Islamic places. So far, the strategy to create modern democracies is bringing paltry results.

Newsweek international editor Fareed Zakaria, who once spoke in Charleston at the Gazette-WVU Festival of Ideas, says moderation is growing in the Islamic world, with intelligent leaders trying to curb "the violence of mobs and the intolerance of masses." We certainly hope this calming trend prevails. Meanwhile, America should leave Afghanistan and let its people build their own future, however they can.