Zinni is a product of the Unified Command structure, which gives the military too much influence in the conduct of diplomacy. Although the State Department assigns officers to these commands (POLADS) to advise and coordinate their activities, I believe they have become too powerful eclipsing the State Department in the conduct of foreign policy. Because they have all kinds of goodies to hand out, they have better access and more influence with foreign heads of state. Guys like Zinni consider themselves as proconsuls. They lack the area expertise and diplomatic experience.
He also lacks the honor and integrity of a Marine.