I think that is a great sign of maturity to have friends with different political position because it means we are capable of exit the "I have the truth" state and embrace the possibility that everyone has his own perspective on things and have something to teach us, even the dumbest person in the world. 
Are you agree with yourself of some days ago? Yourself froma  year ago? Ten year ago?
Our friend is in his own life path, and it is diffetent from ours because everyone is unique. A different political perspective is just an occasion to learn a bit much of our friendship, what make us similar and what differentiate us.