It seems to me that the third alternative, one that’s actually doable, is to require broadcasters to show campaign messages for free, up to a certain portion of their airtime. The enforcement mechanism would be to make renewel of operating licenses contingent on maintaining that number. This would significantly reduce costs for the campaigns.

However, before we start imagining that this would be a panacea, we need to remember that elections are a zero-sum contest and therefore are all about maximizing competitive advantage. If the money isn’t going to TV stations, then it’s going into direct mail or radio, or anything else that might conceivable aid the campaign. The pressure will always be there to raise more money and outspend the opponent.