But aren’t business people complaining about the burden of taxes and regulations? Yes, but no more than usual. Mr. Mishel points out that the National Federation of Independent Business has been surveying small businesses for almost 40 years, asking them to name their most important problem. Taxes and regulations always rank high on the list, but what stands out now is a surge in the number of businesses citing poor sales — which strongly suggests that lack of demand, not fear of government, is holding business back.

So Republican assertions about what ails the economy are pure fantasy, at odds with all the evidence. Should we be surprised?

At one level, of course not. Politicians who always cater to wealthy business interests say that economic recovery requires catering to wealthy business interests. Who could have imagined it?

Yet it seems to me that there is something different about the current state of economic discussion. Political parties have often coalesced around dubious economic ideas — remember the Laffer curve? — but I can’t think of a time when a party’s economic doctrine has been so completely divorced from reality. And I’m also struck by the extent to which Republican-leaning economists — who have to know better — have been willing to lend their credibility to the party’s official delusions.

Partly, no doubt, this reflects the party’s broader slide into its own insular intellectual universe. Large segments of the G.O.P. reject climate science and even the theory of evolution, so why expect evidence to matter for the party’s economic views?

And it also, of course, reflects the political need of the right to make everything bad in America President Obama’s fault. Never mind the fact that the housing bubble, the debt explosion and the financial crisis took place on the watch of a conservative, free-market-praising president; it’s that Democrat in the White House now who gets the blame.

But good politics can be very bad policy. The truth is that we’re in this mess because we had too little regulation, not too much. And now one of our two major parties is determined to double down on the mistakes that caused the disaster.