[Today, after Afghanistan] the United States has the option of following U.S. strategy in the two world wars. The United States was patient, accepted risks and shifted the burden to others, and when it acted, it acted out of necessity, with clearly defined goals matched by capabilities. Waiting until there is no choice but to go to war is not isolationism. Allowing others to carry the primary risk is not disengagement. Waging wars that are finite is not irresponsible.
The greatest danger of war is what it can do to one's own society, changing the obligations of citizens and reshaping their rights. The United States has always done this during wars, but those wars would always end. Fighting a war that cannot end reshapes domestic life permanently. A strategy that compels engagement everywhere will exhaust a country. No empire can survive the imperative of permanent, unwinnable warfare. It is fascinating to watch the French deal with Mali. It is even more fascinating to watch the United States wishing them well and mostly staying out of it. It has taken about 10 years, but here we can see the American system stabilize itself by mitigating the threats that can't be eliminated and refusing to be drawn into fights it can let others handle.