What is Liberalism? What is Conservatism?

I shy away from being excessively reductive, but if I had to define the political currents of the last century, in the United States it would be as follows:

Liberalism was the critique of the social, political and economic status quo from the turn of the century to the 1970's that resulted in an unparalleled growth in the size and scope of the state . During this time, Conservatism was by and large the defense of the status quo. 

Now we see that Liberalism has become a defense of an unsustainable status quo and at least the more dynamic branches of Conservatism has become its greatest challengers.