I don't disagree with you -- but hey, let's face it ... World War II was the third major U.S. "imperial war" in less than 50 years. Three strikes and you're out, and I contend that by the time 1950 rolled around the U.S. simply could never justify the use of military force all over the globe. The whole purpose of the "half-assed war" approach is to manage these military campaigns in a way that is as politically palatable as possible. This means two things, first and foremost: (1) no compulsory military service, and (2) little or no disruption to civilians in the U.S., even in terms of alterations in our standard of living (e.g., "America is at war, while Americans are at the shopping mall").
Your post completely ignores the “half-assed wars” with France from 1798 to 1790, the First Barbary War from 1801 to 1805, The Second Barbary War of 1815, the Mexican War from 1846 to 1848, the “Banana Wars” in central America from 1898 to 1934, the Philippine–American War from 1899 to 1902, the Russian Intervention from 1918 to 1920, action in the Dominican Republic in 1965, and Grenada in 1983. All wars fought overseas.
Everyone thinks when the US goes to war it’s always total war with a million troops sent into the fray. The record shows that it’s more often a limited engagement with more modest objectives than unconditional surrender.