Last month, the Associated Press reported that residents of Amariya, one of the bastions of al-Qaeda control in Baghdad, turned on the terrorists and, with U.S. help, killed their leader and many of his followers.

The fight is emblematic of a larger trend in Iraq.

The Iraqi government has long declared its determination to root out terrorists in the country. But now, ordinary Iraqis, most significantly Sunni Arabs in Al Anbar province, are putting their lives on the line against al-Qaeda as well.

The story of the “Anbar Awakening” begins in mid-2006, a Marine intelligence officer in Al Anbar declared the province irretrievably lost. The Iraqi government was unable to recruit Anbaris into the police or army. But later that year, a combination of al-Qaeda atrocities and skillful counterinsurgency techniques by U.S. forces convinced Sunni tribal leaders that enough was enough.

Today, more than 12,500 Anbari recruits, most of them Sunnis, are prepared to fight al-Qaeda, despite ferocious counterattacks against them and their families. Violence in the provincial capital has dropped from 108 deaths a week in mid-February to seven in the second week of May. Al Anbar has gone from hopeless to a beacon of hope.

Now the movement against al-Qaeda is spreading in size and across sectarian divides. “Salvation councils” have been formed in ethnically diverse Salahuddin, Diyala and Babil provinces.

Al-Qaeda has responded in characteristic fashion — a campaign of atrocities designed to intimidate or kill its new antagonists. But these efforts have not deterred Anbaris or leaders in other provinces from battling back.

This shift shows that success on the most important front in Iraq is possible, but also serves as a reminder of how fragile the situation is. Iraqi security forces are not yet strong enough to protect their leaders and followers from the terrorists. U.S. troops are vital in this task, and are essential in suppressing Shiite death-squad activity, which remains below 50 percent what it was before the surge began. A reduction of U.S. forces in the coming months would expose these Iraqis to horrific deaths and would turn what might be one of the most important victories we could win against al-Qaeda into an unnecessary defeat.

There are many problems in Iraq beyond al-Qaeda, including sectarianism, Iranian influence and Muqtada al-Sadr’s return to public life.

In the midst of the doubt and fear that grips the United States about Iraq today, it’s critically important to recognize the positive trends. Iraq’s Sunni Arabs, once one of the most supportive communities for al-Qaeda, are now among the most hostile, repudiating their alliance of convenience with the terrorists and risking their lives to fight them. The Anbar Awakening and related events form a trend worth fighting to continue, and Iraqis who now stand with us at their own peril are people worth fighting for.

(Kagan is a resident scholar at the American Enterprise Institute. This essay originally appeared in the Los Angeles Times.)