We recently moved to a pretty diverse town in the US, in the North-East, if it matters. We are not from the US originally, and I am still trying to understand how people express themselves politically. I noticed that people who fly the American flag tend to also have republican posters on their lawns (like "Vote this Republican Dude", or "Guns are Great"), while people without a flag tend to have democratic posters ("We support Planned Parenthood" and so on). Obviously, a rainbow flag also screams liberal, while the thin blue line seems to be conservative, and the "No Step on Snek" is either tea party or libertarian (so usually conservative, unless it's combined with a rainbow flag).

What I don't understand still is the deal with the POW / MIA flag. What does it mean? I know what it means in theory, but in theory the Gadsden flag is anti-British, yet these days, as a way of political expression, it obviously has a different meaning. What sentiment is behind the POW/MIA? Are households that fly it more likely to be liberal or conservative? White or black? Pro-gun or anti-gun?

Thanks!