> If we believe in the "market place of ideas" where validity and accuracy are the sole determiners of success then none should have artificial support.

The "market place of ideas" makes no mention of the speed, likelihood of transmission, or intended audience. The best candidate with the best message still needs to get the message out in a timely fashion (before the election and to the core constituency!). The best product at the best price doesn't matter if the business runs out of money before it can drum up sales... not to mention, real world concerns like collective action problems.

I'd argue the market place of ideas is only the best idea in comparison to the rest.