From a purely engineering perspective we can calculate the optimal amount of interference for a particular band of spectrum. We want just enough to achieve coverage. Any more is simply a waste of power. It is that knowledge of a hypothetically perfect solution that leads us down the path of saying that spectrum should be auctioned off with the network built out by the winning bidder. That, and the idea of using the money generated from the auction to help with the budget deficit. Both of thes...