BTW liberal and conservative are not parties, they are ideologies. Of those Ideologies liberalism is the only ideology that is running in Washington and that goes for both parties. Ironically, there is only a small portion of the Republicans that adhere to conservatism (even though they all platform on it) and of those they are fairly silent. The Democrats and Republicans of the modern era are two shades of liberalism.
I believe we will see a viable third party in the future that will represent the American public, which over 80% of us identify as conservative. This is becasue parties used to be good indicators of ideology. This is no longer the case. As the divide between those in power and the people they represent widen, the gap is opening to allow room for a true "conservative" party.
Parties still give an indicator of ideology and can be helpful, but you are correct that it can't make the choice for us. We must vote for the man not the party.