I, Senator Bob brought to you by Exxon-Haliburton-McDeath-Nike-Coke wish to vote on the current bill sponsored by Mcdonnell-Douglas-Oracle-Pizza Hutt but note that I have received contributions from Sony, Matsushita, LG and the RIAA in favour and Napster, Google and USPS against. The balance of contributions favours the bill so I wish to vote affirmatively.

There's also the question of identity - it's easy to form shell companies to make contributions, and I suspect you'd see even more astroturfing than you do now. "Concerned Citizens for Forest Preservation" contributed to the proponent of the "Sustainable Management of National Parks (log the lot) Bill"... a little back up the chain we find that it's a front group for a bunch of loggers. How do you make the Senators disclose the latter instead of the former?