There are persistent and worrisome reports that they might. The Hill newspaper, for instance, claims that Republican budget negotiators have been discussing cutting defense by $600 billion to $700 billion—considerably more than the already indefensible $400 billion in cuts that Obama has said he would like to see over the next decade.

Obama’s proposed cuts are bad enough; as former Defense Secretary Robert Gates implicitly warned before leaving office, such deep reductions would seriously impair the military’s ability to meet its global commitments. Going beyond what Obama has proposed is simply suicidal—on both substantive and political grounds. ~Max Boot

The $400 billion figure is spread out over twelve years. That comes to an average of a little over $33 billion per year. Christopher Preble responded to the same report that has Boot hyperventilating, and he observed that the $700 billion figure “would amount to a bit more than 10 percent less than current projections over the next ten years.”

Preble also noted that the reductions may not be all that they seem:

As always, the devil is in the details. From what baseline? Over what time period? Would the cuts apply only to the base DoD budget, or all national security spending, including the costs of the wars, as well as the budgets for the Departments of Homeland Security and Veterans Affairs? Most important is timing. If the savings are all backloaded in the out years, they may never materialize. Today’s budgets project spending out five or ten years, and the “savings” really just amount to a new set of projections against that baseline. Plus, these agreements are rarely binding on future congresses; a different cast of characters will be responsible for passing DoD appropriations bills in 2018 or 2020.

The Bowles-Simpson plan came up with $100 billion in spending cuts by 2015 and barely scratched the surface. Domenici and Rivlin’s proposal envisioned a spending freeze:

For the Pentagon, the panel wants to freeze spending at fiscal 2011 levels, which it says would save $1.1 trillion through 2020.

While their proposal was more ambitious in reducing military spending than Bowles-Simpson, Domenici and Rivlin claimed that this would not impair any of the missions that Boot rattled off:

The United States still would be the only nation able to patrol the world’s oceans, deploy hundreds of thousands of ground forces to any point on the globe, and dominate the global airspace with superior combat fighters, long-range bombers, and unmanned aircraft.

We should debate the extent of the U.S. role in the world, and many redundant and unnecessary missions and deployments should be brought to an end, but it is not the case that the level of spending cuts under consideration demands the kind of drastic changes that Boot claims. That doesn’t mean that these changes would be the disaster he predicts, and it doesn’t mean that we shouldn’t consider them. What Boot’s list of missions makes clear is how few of them have anything to do with the actual defense of the United States. These missions may or may not be wise or desirable in some other way, but they aren’t meaningfully contributing to national defense.