Just as tobacco companies are allowed to sell products that endanger our physical health, so are we permitting any corporation to pour millions into ad campaigns to endanger the health of our political discourse — with their profit-driven, special-interest propaganda.  Fine, let’s just ensure they all come tagged with a nifty “Attorney General’s warning,” to protect citizens’ sense of perspective.  Here’s a sample I just mocked up.  Can we make this federal law, please?