Putting a price tag on common resources is not communism by any form of definition. If we view things from a feudal perspective, all common resources were held

Putting a price tag on common resources is not communism by any form of definition. If we view things from a feudal perspective, all common resources were held by the crown. You could only get access to things by purchasing or being given a license to it. One of the things we often talk about is the tragedy of the commons. Things without an owner are gobbled up and this is precisely what's happening. Putting a price tag on externalities is about asserting either a state wide, or even world wide ownership on some resource -- whether it be fish stocks, clean air, electromagnetic spectra, etc, etc, etc. This is completely different than a collective/shared ownership by a group of people. Such an idea does not detract in any way from market capitalism. In fact, giving these common resources an owner who can establish a price for their use is exactly what capitalism is all about. We could even go so far as to enact economic fascism by giving ownership of these resources to "elite" companies who will be able to manage them most efficiently (also read as, "giving ownership of these resources to our friends who will be able to maintain their vast wealth and power eternally"). I only mention it since fascism is about as far from communism as you can get (unless, as is often done, you wrap around on the other side of the spectrum ;-) ). The US has a particular view that government ownership should be kept at a minimum. This idea suffers from the problem of either tragedy of the commons (for unregulated common resources and externalities), or with monopolistic ownership of key resources by certain companies (the latter tending towards an economic fascist ideal). I think it's this idea that somebody has to own this stuff and the government is probably the best somebody to own it that's very difficult to swallow for American ideology. But that doesn't mean it can't change.