[mch82]

> [California legislation] has no practical effect on people in Louisiana

People underestimate the side effects of state-level or city-level legislation. Due to the size of the California economy the laws in California absolutely have practical effects on people in Louisiana. This is why national and international laws and agreements matter.

For example, environmental regulations on automobiles (this interview transcript is obviously one example and needs to be evaluated in the context of alternative information, but I think it's adequate to demonstrate the point that interactions between states are significant to a degree that dismissing them is risky): http://e360.yale.edu/feature/californias_clean_car_rules_hel...