Sometimes a wish can mobilize the will and power to make it come true. The Iraq Study Group (ISG) wishes the US could "engage directly with Iran and Syria in order to try to obtain their commitment to constructive policies toward Iraq and other regional issues." Unfortunately, the US does not possess the types of power to force Iranian cooperation, and even if it did, Iran lacks the capacity to grant America’s wish in Iraq. Still, the Study Group has done a service by making it obvious that the US should not reject dialogue with Iran as a matter of principle.
The ISG assumes that Iran’s "interests would not be served by a failure of U.S. policy in Iraq that led to chaos and the territorial disintegration of the Iraqi state." This is neither entirely right nor wrong. Possible US failure in Iraq can take several forms besides territorial disintegration, and Iranian actors may welcome lesser failures. Multiple factions tussle incessantly in Iran’s power circles; some will always resist cooperation with the US and pursue tactics to weaken it