Should disaster aid, as a matter of sound public finance, be offset by immediate cuts in other spending? No. The time-honored principle, backed by economists right and left, is that temporary bursts of spending — which usually arise when there’s a war to fight, but can also arise from other causes, including financial crises and natural disasters — are a good reason to run temporary budget deficits. Rather than imposing sharp cuts in other spending or sharply raising taxes, governments can and should spread the burden over time, borrowing now and repaying gradually via a combination of lower spending and higher taxes.

But can the U.S. government borrow to pay for disaster aid? Isn’t the government broke? Yes, it can, and, no, it isn’t. America has a long-run deficit problem, which should be met with long-run budget measures. But it’s having no problem at all borrowing to pay for current expenses. Moreover, it’s able to borrow funds at extremely low interest rates. Notably, right now the interest rate on the benchmark 10-year U.S. government bond is only slightly more than half what it was in 2004 when Mr. Cantor felt that it wasn’t necessary to pay for disaster relief.

So the claim that fiscal responsibility requires immediate spending cuts to offset the cost of disaster relief is just wrong, in both theory and practice. As I said, it’s just a cover story for the real game being played here.

Now, Mr. Cantor may end up backing down on this one, if only because several of the hard-hit states have Republican governors, who want and need aid soon, without strings attached. But that won’t put an end to the larger issue: What will happen to America now that people like Mr. Cantor are calling the shots for one of its two major political parties?

And, yes, I mean one of our parties. There are plenty of bad things to be said about the Democrats, who have their fair share of cynics and careerists. There may even be Democrats in Congress who would be as willing as Mr. Cantor to advance their goals through sabotage and blackmail (although I can’t think of any). But, if they exist, they aren’t in important leadership positions. Mr. Cantor is. And that should worry anyone who cares about our nation’s future.