Dating partners of opposite political parties can work if each person is either disinterested in politics or has moderate views. On the other hand, if both are political junkies and are extreme Liberals and Conservatives the relationship probably will not survive.
As an on line dater I have found that it is better to explore this topic early so as to avoid later conflict. I state in my on line profile that I am politically Conservative. When e-mailing potential dates I have been rebuffed and done my share of rejecting based solely on our polarized political viewpoints.
I think it is better to face this up front in a new relationship so as to avoid trouble later. We have wished each other luck in their search and moved on.