Now we are way off topic. But we stumbled into another area I am knowledgeable on.
Minimum resale pricing dictated by a manufacturer is allowed in the U.S. However, the major sticking point is that a manufacturer has to have a zero-tolerance policy for dealing with retailers who violate the resale price restrictions in order to avoid violating anti-trust restrictions. I always point out that this would require a manufacturer to cease business with their best retailer if the retailer violates the policy. Generally, this is enough to discourage this practice.
Bingham McCutchen has a really nice 5 page article that goes into all of the legal details: