Democrat Christians care about peacemaking, the poor, immigrants, and the oppressed in our society. To them, this is what it means to be a Christian. So, they vote for Democrat candidates who at least “seem” to care about poverty, war, immigration, civil rights, and the average joe on the street. Republican Christians tend to care about the unborn, the traditional family, and the right to bear arms. Therefore, they vote for Republican candidates who at least “say” they care about overturning abortion laws, defending traditional definitions of marriage [anti-gay marriage, etc.], and protecting the Second Amendment. Both sides firmly believe that to vote any other way is “un-Christian”, but only because they have both developed and accepted a very narrow definition of issues that are “Christian” issues and conveniently ignore those other issues.
Source: How Can You Be Christian And Vote Democrat/Republican? | Keith Giles