In any highly fluid political situation, you will always find some observers determined to argue that it’s not fluid at all–that underneath the surface, the status quo prevails, and anyone thinking otherwise is naive or poorly informed.

Tuesday night, you just knew that Mark Kirk’s U.S. Senate primary victory in Illinois would be interpreted in some circles as proving that the much-discussed rightward trend in the Republican Party, sped along by pressure from the Tea Party Movement, was actually a mirage. And sure enough, Politico‘s Jonathan Martin published an article today entitled: “Tea leaves: Republican establishment Still Rules.”

Aside from Kirk’s win (more about that in a moment), Martin’s main bits of evidence for his hypothesis are that the Republican National Committee recently rejected an effort to impose an ideological “purity test” on candidates seeking party financial support, and that recent GOP winners like Scott Brown and Bob McDonnell didn’t campaign on divisive cultural issues.

The “purity test” argument would be more compelling if not for the fact that many hard-core conservatives opposed it as insufficiently rigid, ham-handed, or unnecessary. Nobody, but nobody, in the conservative movement is more preoccupied with driving RINOs and “squishes” out of the Republican Party like whipped curs than Red State proprietor Erick Erickson. Yet he opposed the “purity test” as offering ideological heretics a phony seal of approval:

Rome long ago stopped selling indulgences, but conservatives keep right on selling them. Look, for example, at NY-23. The moment Dede Scozzafava signed ATR’s [Americans for Tax Reform] no new tax pledge, she was absolved of all her sins, including voting for 198 tax increases in the New York legislature.

Therein lies the inherent problem with candidates signing off on well meaning pablum — there are no teeth and the party will not serve as its own enforcer.

While I applaud the desire of conservative RNC members to try to put the train back on the tracks, I am afraid this will do what the ATR pledge did in Scozzafava’s case — give a lot of candidates cover to pretend to be conservative.

Plenty of other conservatives opposed the “purity test” on grounds that “grassroots Republicans” were best equipped to police candidates. Some interpreted such rhetoric as indicating a big-tent willingness to tolerate regionally important ideological variations. But as the recent DK/R2K survey of self-identified Republicans illustrated, “regional differences” in the GOP are pretty much a relic of the past in a monolithically conservative party. And nowadays the “grassroots” means conservative activists, who are indeed avid to conduct ideological purification rituals. If there is a significant body of “grassroots activists” fighting to protect the interests of Republican “moderates,” it’s an awfully quiet group.

In general, the “purity test’ furor reminds me of a quip I heard during the Jim Crow era about the relative weakness of the John Birch Society in the South: “Nobody sees the point in joining an organization standing for things everybody already agrees with.”

The argument that the success of hyper-opportunist Scott Brown and stealth theocrat Bob McDonnell “proves” the ideologues don’t have much real power in the GOP strikes me as almost self-refuting. Sure, Brown had a “moderate” reputation in the MA legislature, but that’s not why he became the maximum hero of the Tea Party Movement, whose themes he adopted wholesale. By contrast, McDonnell didn’t need to reassure social conservatives of his bona fides by campaigning on “their” issues; he had proven himself to be “one of them” for many years.

As for Mark Kirk, it’s true that conservative activists don’t like him, and there’s even a chance his Senate campaign will be immensely complicated by a Tea Party inspired third-party effort. But it’s also true he spent much of the primary campaign tacking steadily to the right, flip-flopping on the Gitmo detainee issue, and more dramatically, promising to vote in the Senate against the climate change legislation he voted for in the House. He’s hardly a good example of the weakness of conservatives in the GOP nationally.

More generally, it’s increasingly obvious that what passes for a “Republican Establishment” these days is focused heavily on surrendering to the most immediate ideological impulses of Tea Party and conservative movement activists (who are in fact the very same people in many places) and then coopting them for the 2010 and 2012 campaign cycles. In attempting a takeover of the GOP, the hard right is in many respects pushing on an open door. The RNC chairman, supposedly a “moderate” of sorts, never misses an opportunity to identify himself with the Tea Party Movement. Sarah Palin, who was the party’s vice presidential candidate in 2008, has called for a merger of the Movement and the GOP. Republican Sen. Jim DeMint has argued that they have already more or less merged.

In his piece Martin suggests that the longstanding Republican pedigree of Florida Tea Party hero Marco Rubio somehow proves the “establishment” is still in charge. I’d say it shows that “establishment” is in the process of rapidly surrendering to the “conservative coup” that Martin scoffs at. Charlie Crist, whom Rubio seems certain to trounce in a Republican Senate primary later this year, was without question a major “GOP establishment” figure just months ago, and Rubio was considered a nuisance candidate. Now he’s the living symbol of a “purity test” being applied to Republicans by the “grassroots” to dramatic effect.

Yes, many Tea Party activists continue to shake their fists at the “Republican establishment,” just like unambiguously Republican conservative activists have done for many decades, dating back to the Willkie Convention of 1940. But with some exceptions, they are choosing to operate politically almost exclusively through the GOP, to the “establishment’s” delight.

The emerging reality is that the Tea Party activists are the shock troops in the final conquest of the Republican Party by the most hard-core elements of the conservative movement. It’s apparent not just in Republican primaries, but in the remarkable ability of Republican politicians to repudiate as “socialism” many policy positions their party first developed and quite recently embraced (Mark Kirk’s support for cap-and-trade would have been considered relatively uncontroversial just a few years ago). You can certainly root around and find a few exceptions to this trend, but they are few and far between. And the implicit assumption of Martin’s piece–that the “adults” of the Republican “establishment” will once again tame the wild ideological beasts of their party–is actually dangerous.

This item is cross-posted at The Democratic Strategist.