Remember, none of us will be perfect until Judgement day. A properly worded statement in this case would be that a Christian led of the Spirit could not be a democrat. However, all of us follow blindly after our lusts from time to time. Pray for these people that the Holy Spirit's sanctification of these believers would open their eyes or for their genuine salvation.
Very well put. A Christian "can" be a Democrat/Liberal, but the fact that they are is a symptom of an underlying fundamental problem that needs to be solved. My wife and I were talking just today about how sad we are when we see Kerry signs out and about -- to support Kerry, I believe there must be some sort of "internal" problem or hurting. In reality, if every Christian/Catholic (or those who profess to be) voted based on the principles of scripture, there wouldn't be such a thing as a close election.