https://crsreports.congress.gov
Updated July 30, 2024
Defense Primer: Geography, Strategy, and U.S. Force Design
World geography is an influence on U.S. strategy, which in
turn helps shape the design of U.S. military forces.
World Geography and U.S. Strategy
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
for the last several decades have chosen to pursue, as a key
element of U.S. national strategy, a goal of preventing the
emergence of regional hegemons in Eurasia. This objective
reflects a U.S. perspective on geopolitics and grand strategy
developed by U.S. strategists and policymakers during and
in the years immediately after World War II that
incorporates two key judgments:
• that given the amount of people, resources, and
economic activity in Eurasia, a regional hegemon in
Eurasia would represent a concentration of power large
enough to be able to threaten vital U.S. interests; and
• that Eurasia is not dependably self-regulating in terms of
preventing the emergence of regional hegemons,
meaning that the countries of Eurasia cannot be counted
on to be fully able to prevent, through their own choices
and actions, the emergence of regional hegemons, and
may need assistance from one or more countries outside
Eurasia to be able to do this dependably.
Preventing the emergence of regional hegemons in Eurasia
is sometimes also referred to as preserving a division of
power in Eurasia, or as preventing key regions in Eurasia
from coming under the domination of a single power, or as
preventing the emergence of a spheres-of-influence world,
which could be a consequence of the emergence of one or
more regional hegemons in Eurasia. The Biden
Administration’s October 2022 National Security Strategy
document states: “The United States is a global power with
global interests. We are stronger in each region because of
our affirmative engagement in the others. If one region
descends into chaos or is dominated by a hostile power, it
will detrimentally impact our interests in the others.”
Although U.S. policymakers do not often state explicitly in
public the goal of preventing the emergence of regional
hegemons in Eurasia, U.S. military operations in World
War I and World War II, as well as numerous U.S. military
wartime and day-to-day operations since World War II (and
nonmilitary elements of U.S. national strategy since World
War II), appear to have been carried out in no small part in
support of this goal.
U.S. Strategy and Force Design
The goal of preventing the emergence of regional hegemons
in Eurasia is a major reason why the U.S. military is
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. Force elements associated
with this objective include, among other things
• An Air Force with significant numbers of long-range
bombers, long-range surveillance aircraft, and aerial
refueling tankers.
• A Navy with significant numbers of aircraft carriers,
nuclear-powered (as opposed to non-nuclear-powered)
attack submarines, large surface combatants, large
amphibious ships, and underway replenishment ships.
• Significant numbers of long-range Air Force airlift
aircraft and Military Sealift Command sealift ships for
transporting ground forces personnel and their
equipment and supplies rapidly over long distances.
Consistent with a goal of being able to conduct sustained,
large-scale military operations in Eurasia or the oceans and
airspace surrounding Eurasia, the United States also stations
significant numbers of forces and supplies in forward
locations in Europe, the Indo-Pacific, and the Persian Gulf.
Comparing U.S. Forces to Other
Countries’ Forces
The United States is the only country in the world that
designs 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. The other countries in the
Western Hemisphere do not design their forces to do this
because they cannot afford to, and because the United
States is, in effect, doing it for them. 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,
but only on a much smaller scale.)
The fact that the United States designs its military to do
something that other countries do not design their forces to
do can be important to keep in mind when comparing the
U.S. military to the militaries of other nations. For example,
the U.S. Navy has 11 aircraft carriers while other countries
have no more than one or two. Other countries do not need
a significant number of aircraft carriers because, unlike the
United States, they are not designing their forces to cross
broad expanses of ocean and air space and then conduct
