The United States would still need capabilities for possibly simultaneous additional missions, which would probably be smaller in scale than full-fledged war but could be long in duration. Rather than a two-war paradigm, we would want a “1+2” framework for sizing ground forces — the “1” referring to a substantial regional war; the “2” being smaller, multinational but potentially long-lasting contingencies such as a stabilization effort in Afghanistan (or Syria or Yemen).
Some critics will argue that capacity for even one war is too much, that the nation is tired and broke, that counterinsurgency is passe and ground combat obsolete. We convinced ourselves of a similar argument about counterinsurgency after Vietnam, only to be unready for Iraq and Afghanistan a quarter-century later. No new ground wars may be likely, but we must be ready for the unlikely. If, say, tensions between North and South Korea escalate or the North collapses, leading to large-scale mayhem, U.S. forces would have to move fast, along with South Korean units, to stem any bombardment of Seoul and to prevent nuclear materials from leaving the peninsula.
U.S. forces should also retain a capability to remove Iran’s regime. We would consider such an operation only under the most grave circumstances — say, after a direct Iranian attack against the American homeland rivaling Sept. 11 in scale. We would not have enough ground forces to occupy Iran after a march on Tehran, but we should nonetheless have a conventional military counter to possible large-scale terrorism supported by the Iranian state. A robust one-war potential within the nation’s ground forces, plus some capabilities for lesser concurrent missions, is therefore necessary — but also enough for this moment in history.
Critics will also argue that a one-war paradigm could weaken deterrence. We do not want to trigger aggression from those who believe that America is powerless to deal with more than one ground conflict at a time. Part of the answer to this valid concern, shared by Obama and Panetta, is to plan, should we become engaged in a major land war, to promptly activate part of the National Guard and start enlarging the active-duty Army and Marine Corps. The George W. Bush administration took such action belatedly a few years ago, resisting it even after wars in Iraq and Afghanistan were underway; we need not repeat that mistake.
Ultimately, strategy is about minimizing, not eliminating, risk. The threats from maritime contingencies in the Western Pacific and Persian Gulf, and from fiscal weakness, exceed those from simultaneous ground wars. The U.S. defense budget should be adjusted accordingly.