Conservatism is ideology.
It is the ideology that preserves what may be called the Founding Principles of America, as expressed in the Declaration of Independence, the works of the founders, and their mentors such as Algernon Sidney and John Locke.
The Declaration's preamble seems a very meager foundation for principles. Here's its take on the foundation for principles:
That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness.These principles seem quite pragmatic. The DoI then goes on to invoke prudence. I doubt we can truthfully claim an American ideology to have been in continuous existence from the time of the War of Independence to the present.