Without having read the paper yet, I'm thinking the researchers just might've gotten the cart before the horse: Republicans are just more likely to support the government decision to engage in war. So they wouldn't be voting Republican in protest because their kids are serving and dying. They're proud of that.America has been at war continuously for over 15 years, but few Americans seem to notice. This is because the vast majority of citizens have no direct connection to those soldiers fighting, dying, and returning wounded from combat. Increasingly, a divide is emerging between communities whose young people are dying to defend the country, and those communities whose young people are not.
In this paper we empirically explore whether this divide—the casualty gap—contributed to Donald Trump’s surprise victory in November 2016. The data analysis presented in this working paper finds that indeed, in the 2016 election Trump was speaking to this forgotten part of America. Even controlling in a statistical model for many other alternative explanations, we find that there is a significant and meaningful relationship between a community’s rate of military sacrifice and its support for Trump.
Our statistical model suggests that if three states key to Trump’s victory – Pennsylvania, Michigan, and Wisconsin – had suffered even a modestly lower casualty rate, all three could have flipped from red to blue and sent Hillary Clinton to the White House.
Too, also, there's a very unpleasant (downright ugly) sense of aggressive martyr-ism nowadays about military service: I served. I made a sacrifice for our country, and you didn't. Well, as an old-time liberal, I think our country would better honor those who have served, especially those who signed up to serve because they had few or no other realistic employment options, by not engaging in pointless wars, and instead putting that money and energy into improving our country and those citizen's prospects for earning a respectable living as civilians. "Respect" is a key word. If you're working a convenience store or an assembly plant, you're going to feel that those with college educations and white-collar jobs look down upon you (which they do). That makes military service one of the few ways you can upstage someone in better educational and economic circumstances.
One of the things Democrats have to do is start treating blue collar jobs, and the workers who hold them, as worthy of respect. (Actually, more than that: celebrate them.)
For generations, the American Dream has been to rise above our humbler working-class roots by getting a college education and doing better than our parents did. Democrats didn't realize the dark side of promoting the Dream: by seeking to better ourselves, it not-so-subtly denigrates an entire class: those who have not done so. Over the decades, the result has been blue-collar workers feeling dissed by Democrats, and thus affiliating with Republicans, who've been smart enough to not (publicly) dismiss them as their social and economic inferiors.