Preemption is needed most for nascent industries where the economics are uncertain. It gives investors more confidence to invest in an unproven technology if yo

Preemption is needed most for nascent industries where the economics are uncertain. It gives investors more confidence to invest in an unproven technology if you can at least predict one aspect of the landscape on a national level. Down the road, you can start to relax the preemption (theoretically) and let the market forces keep unwise state regulation in check.