By Paul Krugman — New York Times.

Utah Republicans have denied Robert Bennett, a very conservative three-term senator, a place on the ballot, because he’s not conservative enough. In Maine, party activists have pushed through a platform calling for, among other things, abolishing both the Federal Reserve and the Department of Education. And it’s becoming ever more apparent that real power within the G.O.P. rests with the ranting talk-show hosts.

News organizations have taken notice: suddenly, the takeover of the Republican Party by right-wing extremists has become a story (although many reporters seem determined to pretend that something equivalent is happening to the Democrats. It isn’t.) But why is this happening? And in particular, why is it happening now?

The right’s answer, of course, is that it’s about outrage over President Obama’s “socialist” policies — like his health care plan, which is, um, more or less identical to the plan Mitt Romney enacted in Massachusetts. Many on the left argue, instead, that it’s about race, the shock of having a black man in the White House — and there’s surely something to that.

But I’d like to offer two alternative hypotheses: First, Republican extremism was there all along — what’s changed is the willingness of the news media to acknowledge it. Second, to the extent that the power of the party’s extremists really is on the rise, it’s the economy, stupid.

On the first point: when I read reports by journalists who are shocked, shocked at the craziness of Maine’s Republicans, I wonder where they’ve been these past eight or so electoral cycles. For the truth is that the hard right has dominated the G.O.P. for many years. Indeed, the new Maine platform is if anything a bit milder than the Texas Republican platform of 2000, which called not just for eliminating the Federal Reserve but also for returning to the gold standard, for killing not just the Department of Education but also the Environmental Protection Agency, and more.

Somehow, though, the radicalism of Texas Republicans wasn’t a story in 2000, an election year in which George W. Bush of Texas, soon to become president, was widely portrayed as a moderate.

Or consider those talk-show hosts. Rush Limbaugh hasn’t changed: his recent suggestion that environmentalist terrorists might have caused the ecological disaster in the gulf is no worse than his repeated insinuations that Hillary Clinton might have been a party to murder. What’s changed is his respectability: news organizations are no longer as eager to downplay Mr. Limbaugh’s extremism as they were in 2002, when The Washington Post’s media critic insisted that the radio host’s critics were the ones who had “lost a couple of screws,” that he was a sensible “mainstream conservative” who talks “mainly about policy.”

So why has the reporting shifted? Maybe it was just deference to power: as long as America was widely perceived as being on the way to a permanent Republican majority, few were willing to call right-wing extremism by its proper name. Maybe it took a Democrat in the White House to give some observers the courage to say the obvious.

To be fair, however, it’s not all a matter of perception. Right-wing extremism may be the same as it ever was, but it clearly has more adherents now than it did a couple of years ago. Why? It may have a lot to do with a troubled economy.

True, that’s not how it was supposed to work. When the economy plunged into crisis, many observers — myself included — expected a political shift to the left. After all, the crisis made nonsense of the right’s markets-know-best, regulation-is-always-bad dogma. In retrospect, however, this was naïve: voters tend to react with their guts, not in response to analytical arguments — and in bad times, the gut reaction of many voters is to move right.

That’s the message of a recent paper by the economists Markus Brückner and Hans Peter Grüner, who find a striking correlation between economic performance and political extremism in advanced nations: in both America and Europe, periods of low economic growth tend to be associated with a rising vote for right-wing and nationalist political parties. The rise of the Tea Party, in other words, was exactly what we should have expected in the wake of the economic crisis.

So where does our political system go from here? Over the near term, a lot will depend on economic recovery. If the economy continues to add jobs, we can expect some of the air to go out of the Tea Party movement.

But don’t expect extremists to lose their grip on the G.O.P. anytime soon. What we’re seeing in places like Utah and Maine isn’t really a change in the party’s character: it has been dominated by extremists for a long time. The only thing that’s different now is that the rest of the country has finally noticed.