JONATHAN BERNSTEIN is correct in analysing Ted Cruz's current antics in the Senate as a manifestation of Republican conservative-purity politics. When someone is vowing to use "every procedural means available" in pursuit of a goal he obviously knows he can't achieve, what he's doing is setting up a maximalist ideological test which he can later accuse rivals of having failed. Mr Cruz is positioning himself to run for president in 2016. When he does so, he will have outflanked every possible competitor to the right. If he faces any opponent in his campaign for the Republican nomination who failed to filibuster the appropriations bill in the Senate this week, expect him to denounce that opponent as a weakling and a defeatist who was willing to countenance the health-care enslavement of America in order to win approval as a "moderate" from the cocktail-drinking socialists of the Washington, DC establishment. Expect to hear more, in other words, of this:

Cruz said he owes nothing to party leaders such as McConnell. “Every day in the Senate, I try to remember to whom I am accountable, and it is not elected officials in Washington,” he told The Washington Post in an interview last month. “It is not, with all respect, to the mainstream media. The people to whom I believe I am accountable are the men and women in Texas.”

This sort of feedback loop of ever-more-extreme political purity tests is a familiar enough phenomenon. First, you identify a demon, and spend a few years whipping up a hysterical frenzy over the threat it poses. You want to tie it to a few key words that you can repeat in a derogatory, contemptuous tone of voice, over and over, until the very signifier evokes such a feeling of loathing in your audience that anyone associated with it is contaminated. Let's call it Thing X. Now, most people will think your goal here is to drum up a successful campaign against Thing X and against your opponents, who support it, but this is at most part of the mission. Thing X itself may or may not be terribly important, and your opponents are your opponents; there's not much you can do about them. What is crucial here, though, is that once you've firmly established your followers' revulsion towards Thing X, you can use it to annihilate your "allies"—also known as "rivals"—by accusing them of insufficient vigilance against Thing X.

The examples of this dynamic with which I'm most familiar are inflammatory, because they come from totalitarian countries. For a less controversial example, we can look at the way revolutionary Marxism destroyed Students for a Democratic Society in the 1960s, with ambitious upstarts marginalising and then expelling senior members by accusing them of willingness to accommodate bourgeois capitalist imperialism. Or we can look at the escalating anti-Communist purity tests demanded during the McCarthy period.

It's not clear how much blame we ought to assign to individual Republican politicians for the existence of the feedback loop. In a political environment that rewards extremism, you can hardly fault Mr Cruz for deploying tactics that have made him the GOP's It Boy of autumn 2013. Look at allthemediaprofiles! What we can say is that, looking at previous conservative darlings of recent seasons (Paul Ryan, Marco Rubio), we're well into the stage where the Republican revolution has begun to eat its children.

The question is, can parties pull themselves out of these sorts of feedback loops, and how? Mr Bernstein thinks the answer for Republicans is to have a positive policy programme, any programme, that can serve as an alternative way to certify conservative bona fides, as opposed to the maximalist procedural rejectionism of the anti-Obamacare crusade, where the test is just how much of the process of governance you've been willing to blow up in the doomed effort at repeal. But what would such a policy programme consist of, and most importantly, do Republican voters even want one? Ted Cruz came to Washington with a positive programme of some kind. What was it again? Oh yeah:

So let me suggest an alternative course: opportunity conservatism. Republicans should conceptualize and articulate every domestic policy with a single-minded focus on easing the ascent up the economic ladder. We should assess policy with a Rawlsian lens, asking how it affects those least well-off among us. We should champion the 47 percent.

Which is more likely to win a GOP presidential primary in 2016: championing the 47%, or filibustering Obamacare? I think we know the answer. Pedal to the metal, gentlemen; the cliff is that way.

(Photo credit: AFP)