The economic theory is that Congress can, in its ever-present wisdom, calculate precisely the right amount and timing of temporary tax cuts and spending increases to stimulate the economy. But the tax cut must be temporary so as not to add to the “long-term” deficit. And the tax cut must be targeted, lest it benefit someone who makes more money than Ms. Pelosi and Mr. Summers like.

So they and President Bush gave us the $168 billion temporary tax rebate of February 2008 that goosed official GDP for a quarter but did nothing to change incentives to work or invest. Then they and President Obama gave us the $830 billion spending and targeted-tax-cut stimulus of 2009, which included the temporary making-work-pay tax credit and later the temporary home buyer’s tax credit…

The larger point here is that the fiscal cliff is an entirely made-in-Washington fiasco that is the result of bad policy choices. It reflects a dominant political class—mostly Democrats but increasingly many Republicans and conservative intellectuals—who think that growth derives from government spending and that tax rates don’t matter. Until that policy fever is broken, the Beltway’s cable ratings aren’t likely to improve.