Article XI, section 3(a) of the California Constitution authorizes the adoption of a city charter and provides such a charter has the force and effect of state law. Article XI, section 5(a), the “home rule” provision, affirmatively grants to charter cities supremacy over “municipal affairs.”
The above quote taken from this website. What this means in theory, if not always in practice, is that the people of a city in the US state of California can create for themselves a charter and using this they can in effect over ride state laws and operate as a near autonomous region bound by the same state consitution but not by most actual state laws. In essence a city can become a secondary state within a state. According to Wikipedia “112 of California’s 478 cities are charter cities”.
When it comes to writing constitutions those Americans have sure been an innovative bunch. Paul Romer also has some innovative ideas on how the Charter City concept might be extended and used creatively to help end poverty and other global problems. He talks about the idea in the following TED video.
Of course Australia also has the equivalent of a charter city. It’s called Canberra. The equivalent of a micro state within the state of NSW. Perhaps a few other cities should also attain independance from state laws. Or perhaps we should set aside space, as we did for the national capital, where new cities can emerge. Even better if they represented zones that avoided federal laws.