The Department of Defense faces the prospects of additional budget cuts on a scale that would swamp all efforts to avoid change. If the congressional Super Committee fails to find an acceptable solution, the Pentagon would have to cut $600 billion. This would mean cutting up to $100 billion from the fiscal 2013 budget alone.

So what is DoD’s plan for dealing with another $600 billion in budget cuts? There isn’t one. According to Secretary of Defense Leon Panetta, there is no plan B, no alternative defense strategy. This means if – or when – deeper defense budget cuts are imposed, the services will go into survival mode. The current air of cooperation and civility between them will come to a crashing halt, jointness will go out the window and each of the services will look for ways to gain resources at the expense of the others while simultaneously dumping undesirable roles and missions. What we could see is the biggest military food fight in at least a generation. The outcome of this fight could profoundly recast the traditional equal division of defense resources among the Army, Navy, Marines and Air Force.

Defense spending is dominated by two cost factors: people and equipment. With respect to equipment, the biggest source of expenditures in terms of both procurement and operations and maintenance is aircraft, fixed and rotary. The second largest expenditure is on Navy ships. All the other equipment accounts, from tanks and vehicles to radios, radars and missiles, constitute rounding errors to the defense budget. Thus, the coming struggle for resources will really be a war between the Army (and, perhaps to a lesser extent, the Marine Corps) on one side and the Air Force and Navy on the other.

The case for a large Army rests on the belief that a security environment with a wide spectrum of potential adversaries and threats requires both the ability for combined arms maneuver operations against large and sophisticated land forces, as well as to mount wide area security operations to consolidate gains achieved in conventional conflict, deal with failed states, insurgencies and terrorists and provide assistance to civil agencies in the event of disasters in the homeland. The Army would argue that only ground forces are able to gain physical, temporal, and psychological advantages over an enemy and to police large swathes of terrain. By their very natures, the Army would insist, neither the Air Force nor the Navy can control territory. Boil it down, and you’ve got what anyone in the Pentagon would recognize as the “boots on the ground” argument.

No less a source than former Secretary of Defense Robert Gates offered perhaps the best counterargument to the Army, one certain to be employed by the Air Force and Navy in the coming food fight. In a speech at West Point on February 25, 2010 he declared: “In my opinion any future defense secretary who advises the president to again send a big American land army into Asia or into the Middle East or Africa should ‘have his head examined,’ as General MacArthur so delicately put it.”

Moreover, he argued, decision makers “must confront the reality that the most plausible, high-end scenarios for the U.S. military are primarily naval and air engagements.” Lacking a plausible conventional adversary, the Army must prepare “swift-moving expeditionary forces” that can deal with missions such as “counterterrorism, rapid reaction, disaster response, or stability, or security force assistance missions.”

Of course, one might well ask the question if “swift-moving expeditionary forces” are what is required why not rely on the Marine Corps? The Marines routinely deploy in Amphibious Ready Groups (ARG) which are small but very capable, self-contained force packages that can exert limited sea control as well as project air and land power ashore. The ARG carries a battalion-size Marine Expeditionary Unit along with its complement of landing craft, V-22 Ospreys and both attack and transport helicopters. With the introduction of the F-35B, any large-deck amphibious assault ship will be able to project airpower like a mini aircraft carrier.

This discussion naturally leads to the question: what about the Navy. Supporters of a large army could point out that the U.S. faces no great maritime challengers, while on land the number of adversaries is growing. While China appears to be toying with the idea of building a serious Navy, this is many years off. Our former adversary, Russia, would have a challenge fighting the U.S. Coast Guard, much less the U.S. Navy. After that, there are no other navies of consequence. Yes, there are some scenarios under which Iran might attempt to close the Persian Gulf to oil exports, but how much naval power would really be required to reopen the waterway? Truthfully, not much, although the Navy would probably need more mine countermeasures capabilities than it currently possesses.

Being something of an equal opportunity critic, Secretary Gates, made this point very directly. He argued in a speech before the Navy League that the Navy has invested too heavily in large aircraft carriers, large-deck amphibious ships, nuclear submarines and missile firing surface combatants. “All told, the displacement of the U.S. battle fleet – a proxy for overall fleet capabilities – exceeds, by one recent estimate, at least the next 13 navies combined, of which 11 are our allies or partners.” Moreover, Gates and others argue that large surface warships are increasingly vulnerable to precision-guided anti-shipping cruise and ballistic missiles. A corollary to the argument that the Navy is oversized is that the Marine Corps is too big and incorrectly focused on a mission, the large-scale amphibious landing, that has not occurred since Inchon in 1950.

Navy advocates counter by pointing out that the current array of naval forces provides tremendous operational flexibility and freedom of operations on the open oceans. U.S. aircraft carriers, large deck amphibious warships, SSGNs and cruisers allow commanders to deploy lots of firepower as well as to carry unusual cargoes and support a wide range of operations. This can include deployment of Army units and helicopters, the movement of humanitarian relief supplies and the operation of special forces troops. As the number of U.S. overseas bases declines and the remaining few grow increasingly vulnerable to adversaries growing arsenals of long-range precision-guided weapons, the mobility and standoff provided by robust naval forces will become even more important in future military operations.

So, what about the case for airpower? There is certainly an argument for airpower in support of military operations and the Air Force as a provider of services. This role includes everything from the operating satellites, conducting ISR missions with manned and unmanned platforms, airlifting troops and supplies into theater. But all these functions could be provided through joint organizations such as Transportation Command or the National Reconnaissance Office Even the Air Force’s role in providing close air support to the Army could be subject to revision in view of the latter’s acquisition of a wide range of unmanned aerial systems (UASs), armed helicopters and precision guided missiles, artillery projectiles and mortar rounds.

The case for a big Air Force depends on the likelihood of high-end conventional conflicts which would require a fight to attain air superiority and then the conduct of a large-scale, long-range strategic air offensive. Since such conflicts are considered unlikely for years to come, air power advocates will point to the Balkans air campaign, the initial operations against the Taliban and even the Libyan air campaign as models for the role of air (and sea) power in the future. Of course, the fact that the Libyan campaign was conducted successfully by a handful of mostly European aircraft — supported by the U.S. Air Force’s tankers, electronic warfare aircraft and UASs — might suggest that for most future scenarios, the air service is massively oversized.

Were it not for September 11, the fight over the balance among the four services would have taken place more than a decade ago. Some might remember reports in the summer of 2001 that Secretary of Defense Rumsfeld was preparing to cut two Army divisions based on the argument that future wars would be fought not with boots on the ground but with so-called transformational capabilities. Now, as the nation emerges from the time warp created by the al Qaeda’s attacks, the time for the food fight is finally upon them.