http://www.nbr.com/commentary.html#0ALAN BLINDER, FORMER VICE CHAIR, FEDERAL RESERVE: Both President Bush and Senator Kerry have pledged to halve the budget deficit within four or five years. The two promises sound alike, but one of them is more believable than the other. The main reason is a seemingly obscure difference: the budget enforcement rules that Kerry favors but Bush opposes. To understand the issue, we need to go back in history a bit, ironically, to the landmark 1990 budget agreement under President Bush the first. That agreement created two rules. One placed a cap on each year's discretionary spending. The other was the so-called "pay-as-you-go" rule that required Congress to provide a way to pay for any proposed tax cut or increase in entitlement spending. Those rules turned out to be remarkably effective. In conjunction with the sharp change in budget policy under President Clinton, and the booming economy, they helped turn a huge and growing deficit into a large surplus. But then, tragically, the budget rules were eliminated under President Bush the second. What a mistake. It allowed Congress to avoid any serious discussion of how to pay for the 2001 tax cut, or the 2003 tax cut, or the new prescription drug benefit for Medicare. You get the point. So there is a difference. Senator Kerry would enforce his budget promises by bringing back the highly-successful pay-as- you-go rule. President Bush would not. He just wants us to trust his new-found budgetary probity. Which version do you find more credible? I'm Alan Blinder.