Geography, Strategy and U.S. Force Design

Congress gets a briefing

Geography shapes America’s strategy, which shapes American military strategy, which shapes force structure in unique ways that our Eurasian allies and enemies do not reflect given their own geography. Since the 1898 Spanish-American War, America transitioned from holding our ground against stronger European military powers sailing here to intervening in Europe (and then Asia) to prevent threats from growing to a size to cross an ocean and threaten America directly. And the military capabilities of our allies and potential enemies influence our force structure and foreign policy, including a decision to use military force.

The Congressional Research Service has a great brief on geography, strategy, and designing military forces for those factors. The starting point:

World geography is an influence on U.S. strategy, which in turn helps shape the design of U.S. military forces. Most of the world’s people, resources, and economic activity are located not in the Western Hemisphere, but in the other hemisphere, particularly Eurasia. In response to this basic feature of world geography, U.S. policymakers beginning in the 1940s chose to pursue, as a key element of U.S. national strategy, a goal of preventing the emergence of regional hegemons in Eurasia.

While it was an explicit decision in the 1940s, entering World War I in 1917 reflected that need; and the Spanish-America War in 1898 was the last war fought against a European power in this hemisphere,¹ paving the way for intervening in the European balance of power to prevent threats from crossing the Atlantic to attack America.

That threat—actual or potential—is longstanding if not generally recognized today:

And the threat applies to the Pacific since the rise of Japan and now—with Japan a close ally—the rise of China.

This geography and the amount of actual and potential military power in Eurasia has shaped American military structure:

The goal of preventing the emergence of regional hegemons in Eurasia is a major reason why the U.S. military has been structured with force elements that enable it to deploy from the United States, cross broad expanses of ocean and air space, and then conduct sustained, large-scale military operations upon arrival in Eurasia or the waters and airspace surrounding Eurasia.

That security need is unique:

The United States is the only country in the world that has designed its military to be able to depart one hemisphere, cross broad expanses of ocean and air space, and then conduct sustained, large-scale military operations upon arrival in another hemisphere.

Conversely:

Countries in the other hemisphere do not design their forces to do this for the very basic reason that they are already in the other hemisphere, and consequently instead spend their defense money primarily on forces that are tailored largely for influencing events in their own local regions of that hemisphere. (Some countries, such as Russia, China, the United Kingdom, and France, have an ability to deploy forces to distant locations on a much smaller scale.)

I’ve noted that this unique need requires America to spend on large specialized military capabilities that other countries in Eurasia who are in the middle of the theater don’t need in their force structure:

As I’ve observed, we have to go a long way to fight, but Eurasian countries fighting their neighbors (or us) may just need to take off, leave port, or pass through their base gate to be in the combat zone.²

This requires judging the ability of our military to provide the military security America needs in a way that does not rely on direct comparisons to other countries. I wrote this over twenty years ago regarding China:

Every once in a while I will note some article that describes a Chinese weakness. Those who disregard China as a threat like to point these out, too, in order to discount China as a threat to us.

I point them out, note that I wouldn’t want to trade places with China, and then note that it doesn’t matter. Not that power comparisons are irrelevant but that geography must be considered, too. A China that is twice as strong as it is today could not threaten us here in the Western Hemisphere. A China twice as strong would be a force to be reckoned with in East Asia.

And that is what is important. We can project significant power globally. But when China can project significant power 500 miles from their shores, they will be a major threat to our interests, as I noted here:

In World War II, neither Japan nor Germany (and certainly not Italy) were global powers. Yet they were threatening enough, were they not? Get over the idea that a threat is only a threat if it can reach St. Louis. And really, if the Chinese get their way within 500 miles of China against our allies, the impact will reach St. Louis.

This is what the CRS briefing is referring to. We need much more spending just to get to the theater and then sustain our forces there—before we even compare our actual combat power in contact.

The fact that Eurasian powers have other Eurasian powers near them also shapes how they view individual conflicts differently than America does. Ukraine, for example, is worried that the Iran War of 2026 is harming Ukraine. That may or may not be correct. But Zelensky can be forgiven for believing his war for survival is the only relevant fight; while America sees it as “merely” one campaign—that allies can carry more of the weight for—in a global struggle that America is waging:

Seriously, you can’t call Trump isolationist. He simply has different priorities (and different forms) for American military intervention than our Eurasian allies understandably would like us to have. Oh well. We are all disappointed about something at some point. As Churchill noted, the only thing worse than fighting alongside allies is fighting without allies. We’ll get over rough patches. Don’t let the gauze of time make the past seem like an idyllic period of alliance solidarity.

The report also addresses how the geography of Asia and Europe shape the major types of military power America needs. The Pacific is largely viewed as a theater emphasizing air and naval power; while Europe is largely viewed as a theater emphasizing ground and air power.

Of course, “emphasizing” is the key.

Ground and air power in EUCOM still require naval power to hold open lines of communication across the Atlantic if an enemy challenges NATO control.

And even across the vast expanse of ocean in INDOPACOM, small islands have soaked up significant ground power. And at its peak threat level, American (and allied) ground forces in large numbers fought in Korea and in Vietnam. So American ground forces in significant numbers could have a role in land campaigns around China’s periphery in support of allies. I discussed this in Military Review. I addressed one specific example in this Military Review article about an Army corps-sized formation (2-5 divisions plus supporting forces) in a Taiwan scenario.

One type of weapon that the CRS briefing brings up in particular is the super carrier that thus far America uniquely builds in large numbers. These dispatch supporting air power across oceans where land bases may not exist. Although land bases are certainly quite important notwithstanding the carrier capabilities:

And for the carriers themselves, while I am skeptical they are the best system for sea control missions against peer military forces, they are important for power projection missions against smaller powers unable to pose a significant threat to our carriers.

Unfortunately, proponents and opponents tend to take apples and oranges stances on whether the carrier is vital or obsolete:

Carriers are vital for power projection missions but increasingly too vulnerable to gain control of the seas without heavy losses. But useful again once control of the seas is achieved for power projection roles.

The size of Eurasian threats has shaped the American military’s force structure. Fighting Japan, Germany, and Italy reflected a 2-1/2-war capability. That held in the Cold War in theory, but wasn’t really because the USSR and North Korea provided the “two wars” measure plus the ability to face a smaller threat elsewhere. And in the post-Cold War era³, the standards got weaker, starting with the ability to fight two small opponents in regional wars. Then the ability to fight the two nearly simultaneously. And then the ability to fight one with a margin of error built in (1+).

In the current Era of Great Power competition, we aren’t even discussing increasing our military size to World War II scales. But we are talking about rebuilding our quality and emphasizing our defense industrial base. Which I think is wise as a first step rather than hastily expanding to a hollow military.

Yet we still plan on being a major factor in Eurasia by bolstering allies who we are asking/shaming/pressuring/browbeating into increasing their military capabilities so we don’t need a World War II-level force structure to prevent any single hostile power from controlling the superior warmaking potential of Eurasia.

The CRS briefing quotes the national security strategy stating that for America:

“[s]topping regional conflicts before they spiral into global wars that drag down whole continents” is a priority, and that the United States “cannot allow any nation to become so dominant that it could threaten our interests” and will “work with allies and partners to maintain global and regional balances of power to prevent the emergence of dominant adversaries.”

And I count the European Union as one of the hostile powers that is a threat to control that war potential.

Our priority under the new national security strategy is defense of the Western Hemisphere as the foundation of our economy and defense industrial base. Consider this a broader foundation than I described when discussing friendly Canada and Mexico as the foundation of our military power projection capabilities.

Decisions by our leaders on continuing a policy of intervening in Eurasia to prevent a threat to the Western Hemisphere from developing—and I believe that is the correct strategy—will affect our force structure and capabilities.

With stronger overseas allies and an American willingness not to wait to intervene until it is almost too late to prevent a rising threat from reaching across the Atlantic, America won’t need a World War II-size military to provide for the national security of the United States.

1. Although yes, Japan landed in the Aleutian Islands in World War II.

2. Obviously that isn’t generally literally true, but you get the point.

3. A period with a placeholder name that I now prefer to call the Russian Decline Era.