Debate rages today about the future of America’s ground forces. Gone are the days when serious strategists could suggest that that utility of landpower was receding. Now no one questions its importance. But there is disagreement on the type and number of ground forces that the nation needs.
Among the most contentious points are the size of the force (by how much should the Army and Marines be enlarged?), specialized formations for irregular warfare and stabilization operations, and the role of the reserve components. All of these are vitally important. There is, though, another issue which receives less attention: the relationship between the Army and the Marine Corps—the two primary components of America’s ground forces. Does the United States need two ground forces with virtually similar capabilities? I once heard a perplexed foreign officer say, "I’ll never understand your military—not only does your navy have an army, but your navy’s army has an air force!" Is there a strategic reason for this beyond simple tradition? If not, what should the division of labor within the ground forces be? These are not new questions but are ones that should be asked anew, given the evolving national security environment.
Metz notes that the roles have been divided up by mission and that both have been viewed as interchangable forces with each service doing much of what the other does broadly speaking.
He then offers another option (though it is presented just as an option and not the answer):
But there is also a third option: a geographic division of labor. The Marines, for instance, might be the primary ground force provider for the Pacific Rim and perhaps Latin America; the Army for Africa, Europe, and Central, Southwest, and South Asia. This would allow the services some degree of focus concerning cultural expertise, language, and relationships with partner militaries.
This is an old question. It is one I attempted to answer six years ago (actually, seven, but the issue was published in 2001) in Joint Force Quarterly. I advocated a division in roles between Marine-led urban combat (remember the "three-block war" concept?) and Army-led, large-scale armored conventional warfare; and Marines taking the lead in early small-scale but rapid response and the Army taking the lead only in larger and longer wars.
Focusing on large-scale amphibious operations, I asserted, was a distraction from these Marine Corps major future missions. Non-paratrooper light infantry was a waste for the Army, which should heavy them up as medium forces. The Guard, too, must be prepared to support a longer and larger war, I stated.
I did not mention Army special forces, who in peacetime support local forces by understanding local cultures. This isn't a warfighting job, however. And Marines have joined Special Forces Command.
Nor did I mention the idea of simply making the Marines part of the Army. My background is Army (in the Guard variety), but I would not disband a separate Marine Corps as a duplication of effort. It has served us well and it has a tradition that could not be bought, and which must not be tossed away for some paper savings.
I don't like the geographic division idea. This requires each ground service to mirror each other to provide similar capabilities in each service's primary area of operations. As operations in Iraq are showing, brigade-sized units from each service can be commanded by generals from the other service when capabilities of Army and Marine units must be mixed. By letting each service do what it does best (with allowance for adaptation in a longer war), we provide a broader range of capabilities around the globe.
