- It is useful to understand the concepts of existential threat and existential risk, but not if the lesson is overlearned. Beyond the (crucially important) task of batting down fearmongering about new threats, consideration of existential threat for the US are at present is not particularly relevant. It is a major problem if policymakers and the public believe that the world is more dangerous today than it was during the Cuban Missile Crisis, but beyond counter-messaging the topic of existential threats have really little to tell us about international security today.
- For a state like the US, the overwhelmingly majority of threats will be non-existential. Still, the state not only has responsibility to protect its citizens but a universally acknowledged legal right to self-defense. Now, that right can be endlessly defined, interpreted, and quibbled with, but it exists. Second, DIME tools are also useful in and of themselves for creating freedom of maneuver in the international sphere. The ability to employ military force or coerceive diplomatic, economic, or covert tools gives states options.
- Military force is also "fungible"--even outside war, the use of military force as a shaping tool can create political and economic benefits. As Robert Art argues, the military relationship the United States had with Europe and Japan during the Cold War allowed it to define the nature of the economic and political systems it wanted in those states. The US not only protected those states from the Soviets but also created assurances that Germany and Japan would not re-arm.
- Arms, as per Tom Schelling, also enable psychological and political signaling. One of the major reasons why carriers endure, despite concerns about their battlefield utility against high-end Chinese weapons, is the fact that sending an carrrier off the coast of a country still sends a message in most of the world. Whether or not the message is heeded or even interpreted correctly is a matter of context.
The point of these observations is not to take a position on sequestration but to observe that the discussion around existential threats, while valuable, should not be taken too far. One need only look at Maoist China during the 1960s as a consequence of why. China's military forces were good for defeating an conventional land invasion, but little else. As the country's international ambitions changed, its defense strategy shifted from the concept of "luring the enemy into the deep" into an evolutionary consideration of ever more flexible potential uses of military force. And in turn, efforts were mounted (and are still ongoing) to turn a large ground army with little power projection capabilities into a mobile, network-enabled force with the capability for local wars. China's economic success and population gives it a seat at the table, for sure, but regionally its potential ability to turn those resources into military power forces its neighbors, at a minimum, to pay attention.
As Dan has observed, the Founders of our own country clearly wanted a Navy that would be capable of exerting American influence abroad, a dream that reached maturity with Theodore Roosevelt's Great White Fleet. That has some major consequences--200 years of discretionary wars being a prominent one. But those wars have not had the human and material consequences, of say, the wars of Louis the XIV because they have rarely threatened major powers or depleted the American treasury. That is the difference between a continental power that constantly wages discretionary land wars with major powers and a naval/air/cyber one that targets middle and small states and violent non-state actors.
Population-centric counterinsurgency in Iraq and Afghanistan, in light of the current fiscal situation, is an exception to the general rule because supporting and protecting large amounts of military and civilian manpower on the ground is fiscally wasteful and opens up those forces to attacks when they use local transportation infrastructure (or lack theorof). But this doesn't mean that discretionary wars will stop. And, as we have both written, drones have extremely little to do with it.
How much military forces are necessary today? That depends on how one calculates American security, economic, and legal interests and the ability of military forces to achieve them, a debate that is also larger than one blog post can wade into. The point of this series has been to hammer out a baseline for discussion.