Politics and religion should never mix. The reason is from a faith perspective primarily. Which party do you think Jesus would join if He were on Earth today? Making statements like "A Democrat can never be a Christian" is extremely harmful to our Christian outreach. YOU automatically cut the group you can effectively reach with the gospel by making a statement like this one. That's why the SBC is less effective in gaining converts to the Lord. Does that really make you feel good?
I don't care whether you agree with me or not. You're set in your ways. I feel comfortable in sharing what I've done for the Lord at the Last judgement.
I think it is wrong to say "A Democrat can never be a Christian." That would imply they are beyond God's grace. However, I would say A Christian can't be a Democrat. How can you support abortion which is a fundamental statement in the Democrat parties political position? I also believe homosexuals are not beyond God's grace, so should also be ministered to.