Excellent essay, I am glad you posted it and are sending it to friends and relatives. People do need to understand what their vote means.
But just reading the title (as a lot of people do) people get the impression you are advocating that Christians should vote FOR Dems.
You might want to ask the Admin Moderator to add the NOT in your title, as in "Why should Christians NOT vote for Dems".
When you say it, you can convey by the emphasis what you mean, but when it's written, it gives the impression, which is clearly not what you had in mind.
You don't think the question mark makes the point that it's an issue of contention in the article?