How about an elections control board?
It would consist of a group of regular citizens who would take all the contributions normally given to politicians and then monitor the use of TV, radio and newspaper advertising. If candidate A wants a 30 second ad on TV, candidate B gets an equal spot.
Also, the board would screen all ads for negativism. No bashing the opponent, run on one’s own merits. Most critical ads are half truths, taken out of context. If candidates can’t provide proof of their claims, then they don’t get published in any form.