It's mostly not a DoD thing. I'm sure they played a role but like. The American people are perfectly capable of being jingoist on their own.

Primarily, it's a combination of - one, the portion of the US population that has actually served in the military in a war has been consistently declining over decades and decades. Two, there was a huge backlash against the complexity and muddiness and shame of America's involvement in Vietnam, beginning in the 1980s, where a lot of Americans really *wanted* a simplistic good-and-evil version of American military power blowing stuff up really good.