A European said online that Americans blindly followed their President (George W. Bush, at that time.) I disagreed.
A Canadian then explained that I was a typical American who took his opinions from television.
Three of my grandparents were Marxists; the fourth was an anarchist. This is not a typical American heritage. And I don't watch television.
And to the best of my knowledge, I don't know any American who take their opinions from television. Most Americans can easily find TV pundits they already agree with.
What follows will be US-concentric for two reasons. First, the US is the country whose politics and inhabitants I understand best. Second, I expect most of those who read this are Americans; and most of the remainder would like to sell to American markets.
Some conservatives wonder why American Jews don't vote Republican. After all, Jews have done so well thanks to capitalism.
Some liberals wonder why non-wealthy rural Americans do vote Democratic. They've gotten so many benefits from liberal lawmakers.
Here's how to find out why Those People vote the wrong way: ask them. Don't ask conservative experts on liberalism, or liberal experts on conservatism.
Of course, maybe you don't really need to get inside their heads. You only want to write dialog for characters built from cheap and nasty cardboard. If you're a liberal, you can get everything you need by reading The Nation. If you're a conservative, you can get everything you need by reading National Review.
And after that nice fellow in Nigeria gives you all the money he's promised, you'll have more than enough for self-publication.
Ever read fiction set in your area, by someone who's never been there? Fiction with a character in your profession, by someone who you can easily tell is an outsider? A story about people your age, by someone who's obviously much older or much younger?
You need to talk with Those People -- and you need to listen to them during the conversation. You need to read books, blogs, and magazines written by Those People. And ideally, at least one of Those People will read your manuscript before you submit it.