Opponents of Prop. 13 make a political miscalculation as serious as that which conservatives did with Social Security. For 30 years, they have tried to dismantle Prop. 13, or modify it. Their efforts are as doomed as the efforts to change Social Security, because Prop. 13 is considered part of the basic social fabric of California. Today, 70% of Californians support it. Some may not like those numbers, but they should understand them rather than fight them.