This is a terrific article. The author clearly understands that the theological and eschatological differences between radical Sunnis and equally radicals Shiites does not prevent them from making common cause against mutual enemies. It is a stinging rebuke to those who contend that such disparate factions could never cooperate.
The disparate factions of Islam are not fully cooperating. We see small examples of cooperation, but not the nightmare scenario.
If the Muslim factions unite behind a single leader (as Bin Laden hoped), we will face a nightmare war against 1.2 billion people consisting of never-ending terrorist attacks on civilians.
Bush's strategy is to create an offsetting Muslim faction (free and democratic) in the Middle East.