But if they each revolve around their own sets of principles then there must not be one single principle.
Sorry, I didn't get that that was what your were looking for. No there is no one principle. Principled Conservatism is a set of principles.
How is it that each is conservative if they each revolve around their own sets of principles? What is the one thing that makes each one "conservative?"
It is a matter of emphasis or focus. As an example, fiscal conservatives find importance in different things than social conservatives. Fiscal conservatives tend toward capitalism, trade, monetary policy, business and tax issues.
Social conservatives find importance in moral issues - Life, Marriage, the Judeo-Christian Ethic.
Each fight to conserve that which they see as important principles, each holds views considered conservative, preserving the American way - But at least on the surface, while both are important, they don't overlap very much.
But I would submit that, philosophically, the argument for the American way, the argument toward Conservatism, requires both (e.g without a moral people you get crime, drug abuse, bastard children, single parent homes, etc, which create a need for welfare that makes fiscal conservatism impossible)...
The same applies across the factions - while they are all focused on their own thing, fanatically supporting the things they see as beyond price, the truth is that we require them all to preserve any. That, in practice, is Reagan Conservatism.
That is not to denigrate factional conservatives - I admire, and truly appreciate their zeal and adherence to principle. I consider them all brothers in arms. But we only win when we are together, and Reagan makes that possible.