It’s certainly true that Republicans can’t stop a tax rate increase if Mr. Obama is determined to make it happen. The Bush-era rates automatically go up on January 1, and the House can’t extend them alone.

But Mr. Obama also can’t get what he wants without House Republicans. He needs their votes to extend current rates for lower-income taxpayers, as well as to prevent the Alternative Minimum Tax from hitting 27 million more taxpayers. Most of those new AMT taxpayers live in high-tax Democratic states. Meanwhile, the death tax rate reverts to 55% and a $1 million exemption. Senate Democrats running for re-election in 2014 won’t want that on their resume.

For all of his bluster about blaming Republicans, Mr. Obama also knows a budget failure would do enormous harm to his chances of second-term success. It would guarantee at least two more years of trench budget warfare and poison the chances of immigration or other reform. Another recession would be on his watch, not on George W. Bush’s.

The point is that Republicans have more leverage than they imagine, and they ought to act like it.