Why is there no party like this?

[Bond]

Why is there no party in American politics that represents the model of "social liberalism and fiscal conservatism?"

I have always wondered this ever since I began following politics actively many years ago. It seems to me as though many, if not most, Americans think of themselves as socially liberal (pro-gay unions / marriage, pro-equality, pro-reasonable gun control) and fiscally conservative (balanced budgets, low taxes), but neither the Republican nor the Democratic party represent these views. Why?

The best answer I have come up with is that the Republican and Democratic party rely on the radical fringes of their base for the vast majority of the fundraising money they receive, so, in essence, they must cater to the radicals' policy demands. Of course, I also could be wrong, and not many citizens are socially liberal and fiscally conservative.