It is even sadder when we begin thinking and saying things that make it seem like being a Christian is synonymous with being a Republican or a Democrat, and that brethren are lost if they vote a certain way or believe a certain way politically (This is the sin of partiality, and it violates what Paul teaches in Romans 14). We can badly injure a brother or sister over saying someone is less Christian if they have a different political affiliation. No party in U.S. politics is a "Christian" party. Neither is "more Christian" in their beliefs and platform. All of the major political parties have views that are morally evil and contradict scripture. They are not FOR the kingdom of God. They are part of this world, and we need to be careful about the level of love and devotion we show towards a party or their presidential candidates.
We need to be more concerned for souls; the souls of democrats and republicans; the souls of those who are pro-life and pro-choice, and we show a concern for the souls of these people, not by changing their views on the hot-button political issues or leading them to change their political party, but instead by obeying Christ by preaching and teaching the Gospel. Jesus did not say, “Go out into all the world and get the laws changed and change people’s political views.” He said, Go out into all the world and to preach the gospel to every creature” (Matthew 28:19-20; Mark 16:15-16).
And finally, do not forget, as a Christian, you only have one ultimate "political allegiance"; one leader and King that you can submit to and show love for: King Jesus. If your political affiliation leads you to compromise your devotion to your King and His party platform, then your political affiliation has become your idol.