From Human Action — surrounding passage

Capitalism is essentially a scheme for peaceful nations. But this does not mean that a nation which is forced to repel foreign aggressors must substitute government control for private enterprise. If it were to do this, it would deprive itself of the most efficient means of defense. There is no record of a socialist nation which defeated a capitalist nation. In spite of their much glorified war socialism, the Germans were defeated in both World Wars.

“What the incompatibility of war and capitalism really means is that war and high civilization are incompatible.”

If the efficiency of capitalism is directed by governments toward the output of instruments of destruction, the ingenuity of private business turns out weapons which are powerful enough to destroy everything. What makes war and capitalism incompatible with one another is precisely the unparalleled efficiency of the capitalist mode of production. The market economy, subject to the sovereignty of the individual consumers, turns out products which make the individual's life more agreeable.