The State of the Union address was not, I’m sorry to say, very interesting. True, the president offered many good ideas. But we already know that almost none of those ideas will make it past a hostile House of Representatives.

On the other hand, the G.O.P. reply, delivered by Senator Marco Rubio of Florida, was both interesting and revelatory. And I mean that in the worst way. For Mr. Rubio is a rising star, to such an extent that Time magazine put him on its cover, calling him “The Republican Savior.” What we learned Tuesday, however, was that zombie economic ideas have eaten his brain.

In case you’re wondering, a zombie idea is a proposition that has been thoroughly refuted by analysis and evidence, and should be dead — but won’t stay dead because it serves a political purpose, appeals to prejudices, or both. The classic zombie idea in U.S. political discourse is the notion that tax cuts for the wealthy pay for themselves, but there are many more. And, as I said, when it comes to economics it appears that Mr. Rubio’s mind is zombie-infested.

Start with the big question: How did we get into the mess we’re in?

The financial crisis of 2008 and its painful aftermath, which we’re still dealing with, were a huge slap in the face for free-market fundamentalists. Circa 2005, the usual suspects — conservative publications, analysts at right-wing think tanks like the American Enterprise Institute and the Cato Institute, and so on — insisted that deregulated financial markets were doing just fine, and dismissed warnings about a housing bubble as liberal whining. Then the nonexistent bubble burst, and the financial system proved dangerously fragile; only huge government bailouts prevented a total collapse.