When was the last stupid, militaristic phase of American Imperialism, long decried throughout the world? The Spanish-American War, 100 years ago. In the space of roughly 15 years, through Presidents McKinley, Roosevelt and Taft, we took (all from Spain) Puerto Rico, Panama, Cuba, Guam, and the Phillipines Islands. About 100 million people live in those places, today.
According to James Fallows at Atlantic Monthly, the % of Americans in uniform is the lowest since that Imperialistic phase. The same time that Voteview people Poole/Rosenthal illustrate was the point of highest partisanship since today was the 1895-1915 period, which they also correlate with % of foreign born (which is also as high now(11.5%) as any time since the 1900-1915 period, when it reached closer to 15%. A massive resurgence in the KKK, based in Indiana, was a reaction to this)
Perhaps there is a direct correlation between "willingness to send troops to do what we want" and "percent chance you know someone in uniform" are inversely correlated.
In fact, it's absurd to think they aren't.
There are numerous other reasons to see the similarity, including this State of the Union, by President Stephen Grover Cleveland, American Interests in the Cuban Revolution, and this article from Century Magazine in 1898 by Senator Carl Schurz, Thoughts on American Imperialism