The principle of the Separation of Church and State has done wonders for religious freedom, and has brought impressive levels of interpersonal harmony and general prosperity. Why? Because this principle removes the mechanism of violence from religion, making the proposal in explicitly harmonious terms.
Unfortunately, a new kind of violent, crusading morality has taken its place, in the form of economic progressivism. Progressives believe that certain kinds of economic transactions between people, though completely voluntary on all sides, are immoral, and thus must be violently suppressed. This has created, on economic matters, the same kind of heated partisan discord that once divided British Catholics and Protestants. In the less civilized corners of the world, the economic crusaders have employed corruption and military strength to gain a permanent advantage over their opponents, establishing socialist dictatorships.
To restore harmony on economic matters, and ensure that violence is never used for the sake of overly-intrusive, moralistic crusading, what we need is a principle of Separation of Commerce and State.
I believe this principle would function the way the Separation of Church and State has, becoming shorthand for the plea to maintain civility through the enforcement of "live and let live" on economic matters. In other words, you may not agree with the contracts that I agree to, but I am free to make my own choices according to my own economic beliefs, and so are you. Certainly, the progressives will object to such a principle, arguing that the people are too stupid to know what's best for themselves, just as religious crusaders have continued to do, centuries after the introduction of the Separation of Church and state. Yet, I think the formalization of this concept in parallel to the language that protects religious freedom will take a giant leap forward in protecting economic freedom, with far more success than general pleas for liberty (which are often difficult for the uninitiated to understand).
So, have I made my case? Are you ready to start framing the debate over economic liberty in terms of "Separation of Commerce and State"?