The federal government is shut down, we’re about to hit the debt ceiling (with disastrous economic consequences), and no resolution is in sight. How did this happen?The main answer, which only the most pathologically “balanced” reporting can deny, is the radicalization of the Republican Party. As Thomas Mann and Norman Ornstein put it last year in their book, “It’s Even Worse Than It Looks,” the G.O.P. has become “an insurgent outlier — ideologically extreme; contemptuous of the inherited social and economic policy regime; scornful of compromise; unpersuaded by conventional understanding of facts, evidence and science; and dismissive of the legitimacy of its political opposition.”But there’s one more important piece of the story. Conservative leaders are indeed ideologically extreme, but they’re also deeply incompetent. So much so, in fact, that the Dunning-Kruger effect — the truly incompetent can’t even recognize their own incompetence — reigns supreme.

To see what I’m talking about, consider the report in Sunday’s Times about the origins of the current crisis. Early this year, it turns out, some of the usual suspects — the Koch brothers, the political arm of the Heritage Foundation and others — plotted strategy in the wake of Republican electoral defeat. Did they talk about rethinking ideas that voters had soundly rejected? No, they talked extortion, insisting that the threat of a shutdown would induce President Obama to abandon health reform.

This was crazy talk. After all, health reform is Mr. Obama’s signature domestic achievement. You’d have to be completely clueless to believe that he could be bullied into giving up his entire legacy by a defeated, unpopular G.O.P. — as opposed to responding, as he has, by making resistance to blackmail an issue of principle. But the possibility that their strategy might backfire doesn’t seem to have occurred to the would-be extortionists.

Even more remarkable, in its way, was the response of House Republican leaders, who didn’t tell the activists they were being foolish. All they did was urge that the extortion attempt be made over the debt ceiling rather than a government shutdown. And as recently as last week Eric Cantor, the majority leader, was in effect assuring his colleagues that the president will, in fact, give in to blackmail. As far as anyone can tell, Republican leaders are just beginning to suspect that Mr. Obama really means what he has been saying all along.

Many people seem perplexed by the transformation of the G.O.P. into the political equivalent of the Keystone Kops — the Boehner Bunglers? Republican elders, many of whom have been in denial about their party’s radicalization, seem especially startled. But all of this was predictable.

It has been obvious for years that the modern Republican Party is no longer capable of thinking seriously about policy. Whether the issue is climate change or inflation, party members believe what they want to believe, and any contrary evidence is dismissed as a hoax, the product of vast liberal conspiracies.

For a while the party was able to compartmentalize, to remain savvy and realistic about politics even as it rejected objectivity everywhere else. But this wasn’t sustainable. Sooner or later, the party’s attitude toward policy — we listen only to people who tell us what we want to hear, and attack the bearers of uncomfortable news — was bound to infect political strategy, too.

Remember what happened in the 2012 election — not the fact that Mitt Romney lost, but the fact that all the political experts around him apparently had no inkling that he was likely to lose. Polls overwhelmingly pointed to an Obama victory, but Republican analysts denounced the polls as “skewed” and attacked the media outlets reporting those polls for their alleged liberal bias. These days Karl Rove is pleading with House Republicans to be reasonable and accept the results of the 2012 election. But on election night he tried to bully Fox News into retracting its correct call of Ohio — and hence, in effect, the election — for Mr. Obama.

Unfortunately for all of us, even the shock of electoral defeat wasn’t enough to burst the G.O.P. bubble; it’s still a party dominated by wishful thinking, and all but impervious to inconvenient facts. And now that party’s leaders have bungled themselves into a corner.

Everybody not inside the bubble realizes that Mr. Obama can’t and won’t negotiate under the threat that the House will blow up the economy if he doesn’t — any concession at all would legitimize extortion as a routine part of politics. Yet Republican leaders are just beginning to get a clue, and so far clearly have no idea how to back down. Meanwhile, the government is shut, and a debt crisis looms. Incompetence can be a terrible thing.