So, here’s where we are on the debt limit discussions: Democrats have agreed to large spending cuts, but are holding out for doing something about

a rule that lets businesses value their inventory at less than they bought it for in order to lower their tax burden, a loophole that lets hedge-fund managers count their income as capital gains and pay a 15 percent marginal tax rate, the tax treatment of private jets, oil and gas subsidies, and a limit on itemized deductions for the wealthy.

And Republicans walked out.

Think about it. There’s a significant chance that failing to raise the debt limit could provoke a renewed financial crisis — and Republicans would rather take that chance than allow a reduction in tax breaks on corporate jets.

What this says to me is that Obama cannot, must not, concede here. If he does, he’s signaling that the GOP can extract even the most outrageous demands; he’s setting himself up for endless blackmail. A line has to be drawn somewhere; it should have been drawn last fall; but to concede now would effectively mean the end of the presidency.