[Ft. Worth Star-Telegram] President Clinton's budget for fiscal 1999 contained a masterstroke. His proposal to save the budget surplus until Social Security is reformed has stymied Republican tax cutters. Many have wrongly interpreted the president as saying that the surplus should be devoted to shoring up the present Social Security system. It would be tragic if that were the outcome. The present system is not sustainable. Using the surplus to support it will only postpone the date of bankruptcy.