You should be able to set a charge for calling you. Every number that isn’t on your “free” list would automatically be assessed a fee. The phone company would get a percentage of the revenue, and you’d be able to adjust the fee to different levels at different times of the day or for different seasons. (The nearer the election, the higher I’d make my charge.) If candidates really think it’s valuable to call me, they should be willing to pay.
(Link via Glenn Reynolds.)