If there is one exchange in tonight's debate that just might have long-term consequences for the campaign, it is this innocuous-seeming one, in response to Jim Lehrer's annoying insistence that the candidates explain what they would do to finance the Wall Street bailout:

MCCAIN: How about a spending freeze on everything but defense, veteran affairs and entitlement programs.

LEHRER: Spending freeze?

MCCAIN: I think we ought to seriously consider with the exceptions the caring of veterans, national defense and several other vital issues.

Here's why it might matter: McCain has always talked about reducing spending, but has safely dodged almost all specifics on actual spending cuts, other than "earmarks" (which are not cuts at all, whatever the percent of the budget) and some defense systems like "Future Combat Systems," and some vague nonsense about savings from "victory" in Iraq. A spending freeze, on the other hand, is a very specific thing -- some programs will be in the freeze, some out. In a recession, programs that would normally cost more automatically -- like Food Stamps or Unemployment Insurance -- will be unable to respond.

Over the next few weeks, Obama (as well as the press, if it's not to much to ask) should pound relentlessly on the spending freeze: What's frozen, and what's "several other vital issues"? In a recession, are Food Stamps frozen? Student loans? Unemployment benefits? Pell Grants? S-CHIP? Low-Income Home Energy Assistance (LIHEAP)? The list is long, and different states and constituencies naturally have their own programs that they would like to know whether McCain would freeze them or not.

And wherever McCain's answer is yes, that program would be part of the freeze, numbers can usually be put to it quickly. For example, freezing LIHEAP would leave X million seniors without heat this winter. Freezing Pell Grants would mean X million students couldn't go to college.

At the end, McCain will be in one of two boxes: Either he's a guy who is willing to slash every domestic program, leave seniors in the dark and kids blocked from college, while dumping hundreds of billions of dollars into Wall Street and Baghdad, plus his tax cuts. Or his "spending freeze" is just another vacuous gimmick.

-- Mark Schmitt.