The Nonintervention DelusionNovember/December 2019 93U.S. military interventions take diverse forms—an isolated drone
strike in a remote area o Pakistan is as dierent from a theoretical future
war with China as is possible to contemplate. As a result, there are no
precise rules about when leaders should and should not use force. Context
matters, and human judgment always comes into play. Yet it is possible
to sketch out several principles, informed by the experience o recent
decades, that should guide the general conduct o U.S. decision-making.
The Ärst guideline is to avoid overlearning the supposed lessons o
past interventions. It’s often said that generals are always Äghting the
last war, and the same can be said o policymakers. Sometimes, they
draw the right lessons, but sometimes, they do not. President Harry
Truman sent troops north o the 38th parallel in Korea, drawing
China into the Korean War, so in Vietnam, U.S. ground forces re-
mained on their side o the demilitarized zone—which put enormous
emphasis on extensive bombing campaigns against the North. Hop-
ing to avoid a Vietnam-style quagmire, when the George H. W. Bush
administration fought the Gul War, it sought to limit its objective to
the speciÄc aim o restoring Kuwaiti sovereignty. But because Sad-
dam was left in power, the Iraq problem festered. The second Iraq war
was supposed to Änish the job—but it showed how a purportedly
short conÁict can lead to an indeÄnite occupation. To prevent that
from happening in Libya, Obama decided to use airpower to help
oust QaddaÄ but keep American boots o the ground; he was thus
unable to contain the chaos that followed. And so in Syria, Obama
and Trump would Äght terrorists without attempting to remove
Assad. Sticking to rigid lines based on prior errors can easily lead to
new and dierent pitfalls.
Another guideline is to pick interventions that meet clear condi-
tions and commit to those that are chosen. The United States should
generally undertake interventions only when political leaders—
namely, the president and a majority o Congress—believe that force
is necessary to attain a clearly stated objective. They should have a
reasonable expectation that allies, especially those in the region in
question, will join the eort, and they should make serious eorts to
enlist them. They should conclude that the beneÄts o a military in-
tervention over the long run are reasonably expected to exceed the
costs. And they should undertake military interventions in which they
are prepared for the possibility that U.S. forces will have to stay for a
long time, indeÄnitely i necessary.