In the seven presidential election cycles since Ronald Reagan won the 1980 Republican nomination, the party’s base has lamented its failure to send another unadulterated conservative to the top of the ticket. Like a perpetual political bridesmaid, the right wing has swooned for ideological soulmates and bickered over potential suitors while establishment candidates such as Mitt Romney have gone on to seal the deal.

But in a deeper sense, those seemingly jilted conservatives do get their man.

Republican candidates have conformed to the needs of a vastly conservative primary electorate ever since the party rejected Romney’s father, George, in 1968; his failed presidential campaign represented an early turning point in the decline of moderate Republicanism. Mitt Romney’s contortions to fit the conservative mold make for a poignant coda to a precedent set by George H.W. Bush, Bob Dole, George W. Bush and John McCain before him.

All of those eventual nominees, to varying but significant degrees, adopted the conservative ideology of their insurgent rivals while inheriting the palatable aura — or in Romney’s case, the lantern jaw — of their moderate forebears. While a Romney nomination may vindicate the family name, it would also complete the conservative eclipse of his father’s moderate vision.

History has compressed the elder Romney’s campaign to his woeful explanation of why he was for the Vietnam War before he was against it (because of “brainwashing” by generals, he said). But at the time, his fiscal conservatism, self-made Midwestern values and emphasis on civil rights set him apart from the party’s fading East Coast liberal wing, represented by New York Gov. Nelson Rockefeller; the surging conservatism of Reagan; and the ideological flexibility of Richard Nixon. Among them, Romney stood as a standard-bearer of moderation in a party that had begun its long march to the right.

“George Romney was somebody who could have revived the moderate Republican fortunes within the party,” said Geoffrey Kabaservice, a scholar who has studied the collapse of moderate Republicanism. “He might have made the party in his own image.”

Instead, image alone has proved to be the strongest legacy of Republican moderates. The centrist diaspora, which has lost the ideological battles but still controls important real estate in the Wall Street and Washington quarters of the GOP establishment, prefers a candidate to whom it can relate. Its members doubt that conservative firebrands and Southern fundamentalists, for all their grass-roots appeal, can win general elections.

“If there is an establishment, we look at who can be elected,” said Dole, the 1996 presidential nominee — who, it should be noted, handily lost the general election to Bill Clinton after overcoming protests on his right from Newt Gingrich and others. Today, he is supporting Mitt Romney. “My man is winning,” he said.

The establishment’s enduring belief that unmitigated conservatives cannot win the big one has its roots in the disastrous nomination of Barry Goldwater in 1964. Not only did Goldwater’s hostile takeover of the GOP convention lead to a rout by Lyndon Johnson, but Republicans suffered in all levels of government, down to local sheriff’s races.

For the GOP grandees, the lesson was clear: put forward a candidate whose platform resonated with the growing and increasingly conservative base, but whose connections and countenance put moderates at ease. According to Kabaservice, the author of “Rule and Ruin: The Downfall of Moderation and the Destruction of the Republican Party,” Reagan himself moderated his conservative rhetoric — and his style of governing — in the years following Goldwater’s defeat.

But after Barack Obama’s 2008 victory, which many conservatives consider an existential threat to their view of America, the current crop of long-shot candidates is arguing that it is time to unlearn the Goldwater lesson and reject another Romney.

‘Only way to defeat Obama’

A few days ago here in Columbia, Gingrich’s campaign bus rolled past a parked red-white-and-blue race car painted with the words “Tea Party” and “Newtmobile.” His party’s internecine struggle, conservatives overpowering moderates, has been the defining mission of Gingrich’s political career. In the decade after Reagan, he inspired his own version of a conservative revolution on Capitol Hill, helping take down the presidency of a Republican moderate, the elder George Bush, along the way.

Now he is engaged in one more battle. His bus pulled to a stop in front of Phillip’s Market, where Gingrich implored attendees at a town hall meeting not to nominate Romney. Speaking matter-of-factly, with his trademark air of certitude, the former House speaker argued that Romney’s record on health care and other key issues would make a sharp ideological contrast with Obama impossible.

“Do you want somebody who is a moderate?” Gingrich asked, adding: “What you want is somebody like this, like Reagan was with Carter. You want a real conservative. . . . The only way to defeat Obama is to nominate an articulate conservative who has the courage to be tough enough to go nose-to-nose with him.”

The crowd erupted, chanting “Newt, Newt, Newt.”

A few hours later, at a candidate forum downtown, Gingrich concluded his pitch to local businessmen by warning that if he didn’t win the South Carolina primary on Saturday, “we will probably nominate a moderate, and the odds are fairly high he will lose to Obama.”

Gingrich the historian has some history on his side. The record of the most moderate-seeming nominees in recent general elections has been lackluster. Gerald Ford held off Reagan at the boisterous 1976 convention in Kansas City, Mo., only to lose in the fall to Jimmy Carter. Both George H.W. Bush and Dole survived conservative insurgencies only to fall to Clinton; McCain bested Mike Huckabee, a darling of social conservatives, only to get trounced by Obama.

After success, divisions

Past conservative also-rans said they relate to the current field’s aggravation, but they also noted that the present conservative predicament is a result of their success a half-century ago in running George Romney and the more liberal Rockefeller Republicans out of the party.

“They are dead, and so we have taken over,” said Pat Buchanan, who lost the nomination to Dole in 1996 after unexpectedly winning the New Hampshire primary. “When the revolution took over, you had the Leninists and the Trotskyites and the Bukharinites and the whole thing. Once the revolution succeeds, it doesn’t mean that we’re all unified. But the new divisions rise.”

“The conservatives have not presented a united front,” Pat Robertson concurred in an e-mail. While the Christian leader, who lost to George H.W. Bush in 1988, lamented that “Republicans don’t consider certain fringe candidates as electable,” he took solace in noting that “for a non-office-holding amateur, my third-place showing in the contest was respectable.”

This cycle, as conservatives sense a rare opportunity to depose a sitting president, they want more than a respectable finish.

Gary Bauer, a leader in the social conservative movement who lost to the “compassionate conservatism” of George W. Bush in 2000, said he had “the Bush train run over me several times.” Last weekend, he helped organize an emergency meeting of evangelicals in Texas to try to find consensus on a conservative candidate to halt Romney’s seemingly unstoppable glide toward the nomination. Former senator Rick Santorum (Pa.), whom Bauer backed, emerged as the nominal conservative alternative. But there is no sudden peace in South Carolina to suggest that Gingrich or Texas Gov. Rick Perry acknowledges him as such.

“There ends up being a number of candidates competing for this vote, and it naturally gets divided,” Bauer said.

He attributed the high number of conservative candidates to the overwhelming success of the Reagan revolution, which, in its utter domination of the GOP, has left little ideological room between establishment candidates and grass-roots contenders. As a result, Bauer said, it is “harder for insurgent candidacies — whether it’s Buchanan or my effort in 2000 — to rally enough discontent with the way things are to be successful.”

‘Try and label each other’

The conservative dominance of the party has also made it easier for Romney to follow a well-worn path toward the nomination. At the debate in Myrtle Beach, S.C., on Monday night, he spent a good portion of his time watching Gingrich, Santorum and Perry joust for the title of conservative king. When not attacking one another on television, in gun shops or at barbecue joints, the three rivals have focused their efforts on tagging Romney as another conservative manque who would govern as a moderate.

But even as Romney’s competitors — especially Gingrich — make a spirited stand in South Carolina, the Romney camp exudes confidence. “Oh, they are doing their job,” South Carolina Gov. Nikki Haley, a Romney supporter, said of the attacks with a dismissive chuckle. “You know in a primary, you try and hit each other. You try and label each other.”

Because of Romney’s moderate pedigree, as well as positions he took as a Senate candidate and as governor of Massachusetts that put him well outside the conservative norm, he has spent the past six years trying to convince conservatives that he is one of them. During the debate in Myrtle Beach, a Twitter user asked him to “convince me you won’t change again.” He renounced — again — any hint of moderation in his past on social issues such as abortion and gay rights, and he launched into a litany of beliefs that placed him firmly within the conservative mainstream.

“I believe in free enterprise, I believe in freedom, I believe in liberty, I believe in an opportunity society,” he said. “And everything I do will be designed to strengthen the values of this country, to strengthen the families of this country, to strengthen our economy and to keep a military that is second to none in the world.”

After the debate, Romney’s advisers continued where he left off. In 2008, some of the same people who are now calling the candidate too moderate “were begging Romney to stay in against McCain, and his positions haven’t changed one iota,” said Ron Kaufman, a Romney adviser. “So there really isn’t a moderate in this race.”

Massachusetts vs. Utah

Kaufman is no stranger to candidates whom conservatives have considered too centrist. In 1980, he worked for George H.W. Bush against the conservative prince, Reagan, and later he played a large role in Bush’s nomination over Robertson and Buchanan, going on to serve as Bush’s White House political director. He said that perceptions of Romney, and himself, as moderates have more to do with the geography and culture of their home states than the ideology they espouse.

“If Mitt didn’t change one comma in one issue but was running from Utah, he wouldn’t be a moderate,” Kaufman said. “It’s more cultural and touchy-feely than reality.”

For now.

Little seems real in a campaign season, especially one as loopy as this one. But for all of Romney’s testaments to his unwavering conservatism, the great fear of conservatives is that he knows what it takes to get elected, and that once in office he would resurrect his father’s moderate sensibility.

“Mitt knows he has to do these things where his father failed,” said Kabaservice, the scholar. “What we don’t know yet is what his turn back towards the center would be like.”