First, notice that, in his speech in Colorado today, McCain nowhere actually promises to balance the budget:
We must also get government's fiscal house in order. American workers and families pay their bills and balance their budgets, and I will demand the same of the government. A government that spends wisely and balances its budget is a catalyst for economic growth and the creation of good and secure jobs.
He just will "demand" it. And he sets no timetable. A memo released by his campaign includes the following line:
"John McCain Will Balance The Budget By The End Of His First Term. The near-term path to balance is built on three principles: reasonable economic growth, comprehensive spending controls, and bi-partisanship in budget efforts. Longer-term, the only way to keep the budget balanced is successful reform of the large spending pressures in Social Security, Medicare, and Medicaid"
The reality is that a President John McCain will propose budgets that are fundamentally at odds with the budgets that a Democratic Congress will pass. If McCain intends to keep his promise to balance the budget, he's going to have to provide more details.
Right now, based on what McCain and the campaign have said, McCain proposes more than $650 billion a year in tax cuts, which is equivalent to a third of domestic spending, and is offset by, first, $160 billion in unspecified domestic cuts. (Note: the McCain campaign disputes the premise that some of the tax cuts, like altering the way companies deduct expenses, would cost anything in the long-run so they don't provide off-sets for it.) The rest would come from economic growth after some sort of rapid sequence intubation of fresh optimism into the economy and large-scale reform of Medicare, Medicaid and Social Security. On a conference call today, McCain adviser Douglas Holtz-Eakin hinted that the onus would be on Democrats to cooperate with McCain on entitlement reform, implying that if they don't, the Democratic Congress would be to blame for the deficit, not McCain. As the multi-partisan Center for Tax Policy concluded, "McCain's reduced individual and corporate rates could improve economic efficiency and increase domestic investment, but the larger future deficits would reduce and could completely offset any positive effect." Another problem is that McCain has not spelled out precisely what type of entitlement reform he would be open to, so we are left to guess. He hasn't, aside from some generalities, provided enough specifics as to federal programs he'd chop down; aside from oil and ethanol subsidies, we don't know how he'd cut corporate welfare or even how he defines corporate welfare. And then there's the war, the cost of reconfiguring DoD for new threats, etc.