On Sept. 7, at the Union League in Philadelphia, Republican presidential nominee Donald Trump gave a major policy speech on defense matters. In it, he proposed force levels for the military services, citing recommendations made in The Heritage Foundation’s Index of U.S. Military Strength.
Following the event, various news outlets and commentators expressed some confusion about the numbers, with specific attention given to the number of tactical fighters recommended for the Air Force. The following explains how Heritage arrived at the force level recommendations provided in the Index.
To develop a reference against which to assess the capacity of the military services to protect U.S. critical national security interests, we reviewed the historical use of forces in major wars following World War II—Korea, Vietnam, Desert Storm, and Iraqi Freedom. We also reviewed all of the major federally mandated or commissioned defense studies since the early 1990s, to include the “Bottom-Up Review” of 1993, the Quadrennial Defense Reviews (QDRs), and the independent National Defense Panel reports. Adjusting for how forces change over time, we found a remarkably consistent set of numbers.
Historically, the U.S. has, on average, committed 21 Army brigade-equivalents, 500 Air Force tactical fighter/attack aircraft, and 15 Marine Corps infantry battalions to a major conflict. U.S. Navy ship numbers are a bit different to calculate since the Navy not only has to be prepared to fight wars but also conducts continuous patrolling in oceans around the world. With respect to the Navy, we looked at both requirements—wartime employment and peacetime presence missions—and used the larger number per type of warship.
Importantly, we embraced the force-sizing argument that the U.S. military should be able to handle two wars in closely related timeframes, i.e. it should have the ability to commit to one war while retaining enough capacity to handle a second major conflict. Having this ability deters other competitors from trying to take advantage of the U.S. being “tied down” in a conflict in one region. This is a problem the U.S. is having today; the U.S. is struggling to maintain its current level of effort in the Middle East while also recovering from more than a decade of operations in Iraq and Afghanistan while still ensuring sufficient levels of forces are either deployed, or able to deploy, to other areas of the world.
Stating the obvious, a “two-war” capable force would be double what has been needed to fight one war. So, 42 brigades, 1,000 fighters, 30 Marine infantry battalions, all of which Heritage recommends should be in the active component—stationed abroad, committed to regular deployment cycles, or “ready for action” on short notice. Forces maintained in the National Guard and Reserve would be additive.
Some forces are always committed to training or important ongoing commitments, thus making them unavailable to rapidly reinforce an action or to replace combat losses. So, we added a 20 percent buffer resulting in a recommended active component force of 50 Army combat brigades, 1,200 Air Force fighters, and 36 Marine Corps infantry battalions.
Circling back to the Navy, historical employment and every major study agrees that a Navy of around 350 ships is solidly justified, a fleet that includes 13 carrier battle groups.
We compared these numbers to all the major studies mentioned above and found them in general agreement with our force proposal. To be clear, four major wars over the past 65 years and nine federally commissioned studies serve as the foundation for our recommendation.
It is important to note that this is an “at least” proposal. Having more than these recommended forces means the margin for success in an extended conflict, when combat losses really begin to mount, increases and risks are reduced. National Guard and Reserve forces contribute mightily in this sense.
“Big wars” don’t happen often—about every 15-20 years—but they do happen with regularity every 15-20 years. When they do happen, it is too late to build the force one needs, especially given the amount of time it takes to manufacture a modern airplane, ship, or tank, build up inventories of modern munitions (“smart bombs,” rockets, and missiles), or for units and major headquarters to train to the level needed to succeed in modern combined-arms combat.
With specific regard to our Air Force numbers, there is an important distinction between aircraft that are “combat coded” and those that are used to test and evaluate aircraft handling, performance, software/hardware updates; develop and evaluate tactics, and train replacement crews for operational squadrons. Aircraft that support test, operational test and evaluation, and training roles are not made available to combatant commanders, and are not "combat coded," which is why they are excluded from Heritage recommended numbers for tactical fighter/attack aircraft. As an aside, A-10 Warthog aircraft were not included in the total because of their limited mission set.
Lastly, the force we recommend represents the “hard combat power” that actively engages the enemy. It is a surrogate measure for the much larger force that includes all of the support capabilities (e.g. supply, transport, maintenance, communications, intelligence, etc.) and institutional military (recruiting, training, schools, installations, headquarters, etc.) needed to make the combat element possible.
All of the above can be found in Heritage’s Index of U.S. Military Strength: an explanation of military power, our approach to the Index in deciding what to measure and what to exclude, the historical employment of forces and related defense studies, and detailed discussions of each of the individual services.
“Peace through strength” rests on the principle that a strong and ready military of sufficient size to protect national security interests on a global scale actually deters enemies from actively threatening U.S. interests. As we capture in the Index, our current military is 2/3 the size it needs to be and of the 2/3 we have, only 1/3 is assessed by the services themselves as “combat ready.”
The trend is bad and getting worse: In the material condition and size of the U.S. military, the increase in threats to U.S. security interests, and in the ability of allies and friends to contribute their share in common cause with America to maintain a world that is free, prosperous, and civil.