Writing as an adjunct scholar with the Middle East Institute, Wayne White notes that the counterinsurgency strategy employed by the U.S. military at the onset of the Iraqi offensive disenfranchised many Shiite Iraqis, pushing them to support the anti-American sentiment that lies at the heart of Sadr's platform.

So much so, White says, that "Sadr and his Mehdi Army may be the only Shiite militia on the Iraqi scene with real street power."

The U.S. military has been quick to point out that Sadr and his supporters receive significant backing from Tehran; however, there are many in the Iraqi political environment who can make similar claims, White notes.

White says that Sadr has increased his influence in the streets of Iraq by providing medical and other basic social services to residents, something U.S. and Iraqi officials have proven unable to do.

"Since the government has shown little ability to deliver, and one major grievance is the U.S. occupation itself, Sadr … probably will remain a robust fixture on the Iraqi political scene for some time to come," White concludes.