A day after beating incumbent Arlen Specter in a Pennsylvania Democratic Senate primary contest, Rep. Joe Sestak announced that he would make "enforcement of the pay-as-you-go budget rules" a priority if he wins in November. Good luck to him.

Pay-as-you-go, or paygo, rules require that new entitlement spending and new tax cuts must be paid for dollar-for-dollar with entitlement spending cuts or tax increases. As Paul Ryan, the ranking Republican member of the House Budget Committee has noted, the Democrats under Speaker Nancy...