By E.J. Dionne Jr.

Suddenly, we are back in the Republican presidential primaries. Mitt Romney's critics on the right showed last week that they still won't cut him slack.

The hard right was apoplectic that Romney refuses to renounce paternity of his health plan in Massachusetts. More establishment conservatives urged that he give them something to vote for by choosing Paul Ryan as his running mate.

This came as Republican voters continued to nominate very right-wing candidates over fairly right-wing candidates in other races. The marquee figure, Ted Cruz, defeated Gov. Rick Perry's choice in a Texas U.S. Senate primary. Getting to the right of Perry takes some doing.

We are witnessing a still-unfinished Republican Revolution. The GOP's primary electorate, its wealthy donors and its talking-and-writing class want to take the party even further to the right than it already is. They have in Romney a nominee who is (1) far more conservative than his moderate father; (2) well to the right of where he once claimed to be in his Massachusetts days; and (3) entirely willing to take additional steps to appease a party base that has been purged of middle-of-the-roaders.

Still, it's not enough.

That only reinforces the reality of Romney as an accidental victor. He survived the primaries because he was the only plausible president in the field. His adversaries held views more in tune with those of the Republican faithful.

But for some fatal mistakes, Perry should have won the nomination, given how closely his philosophical inclinations track those of most Republicans. When Perry imploded, the right-wing flag was picked up by Herman Cain -- he actually led Romney nationwide in some polls last October -- and then by Newt Gingrich and Rick Santorum. Santorum came closer to derailing the Romney machine than we remember.

The party's discontent pushed Romney to do two things that are haunting him now. First, he had to invest heavily in TV spots pummeling Santorum and Gingrich. This aggravated enmity on the right while depriving Romney of the chance to build a favorable public image through positive advertising. Second, Romney was forced into a constant scramble rightward. He is stuck, for example, with a position on immigration that is crippling him among Hispanic voters because he had to find some issue on which to get to Perry's right (Perry being, by contemporary Republican standards, a "liberal" on immigration).

If Romney were now ahead of President Obama in the polls, most of the right would be silent, possibly even happy, since nothing unites the GOP more than antipathy to Obama. But the fact that Romney is still behind -- and well behind in two new polls last week -- gives his conservative detractors license to vent their suspicions that he is still (in Gingrich's old phrase) a Massachusetts moderate.

That's why right-wing talkers such as Erick Erickson, Ann Coulter and Rush Limbaugh denounced Romney spokeswoman Andrea Saul -- Coulter wanted her fired -- after Saul defended Romney against a controversial ad from a pro-Obama super PAC. Saul dared to say that the wife of Joe Soptic, the former steelworker who is the ad's narrator, would have had insurance coverage in Massachusetts under Romney's health care plan even after he lost his job at a company reorganized by Bain Capital.

What Saul said was true. But Romney is not supposed to defend his health plan. And Erickson & Co. correctly noted that Saul's comment opened the way for Democrats to argue that Obamacare, modeled after Romneycare, would have provided her with coverage in the other 49 states. The contradictions of Romneyism are tough on those who speak for his campaign.

The Ryan boomlet, from the editorial pages of The Wall Street Journal, The Weekly Standard and elsewhere, is the conservative elite's way of demanding that Romney base his campaign not on the tactical moves that have largely defined it but on a full-throated defense of radically smaller government. This would include the specifics of the Ryan budget, particularly his Medicare cuts. Yet the more that conservatives insist on Ryan, the more Romney's selection of him would be cast as just another capitulation to the GOP right.

There's nothing wrong with Romney that better poll numbers wouldn't cure. But the lagging numbers themselves reflect widespread uncertainty over who Romney really is. That's a problem with the broader electorate. But it is a particular obstacle for a Republican right that still hasn't found what it's looking for.

E.J. Dionne Jr. writes for the Washington Post Writers Group.