To those who knew them, the ultimate proof of the two men’s bond was reducible to a question: How many fathers would look after their son’s girlfriend in his absence? So much did the teenage Mitt Romney trust in his father George’s wisdom that he gratefully accepted his assistance in nurturing his relationship with his old high school girlfriend and future wife, Ann Davies, during a long separation from her.

By then, the young Romney was in France for two years of Mormon missionary work, and Romney family members, as well as Mitt’s friends, were well aware of Ann’s possible appeal to a slew of would-be suitors. As the popular governor of Michigan, George was already mulling the prospect of a presidential campaign.

But he was also the protector of everything that had to do with his youngest son’s welfare, and so he made Ann a priority in his schedule. He frequently escorted her to church. After one service, he happily wrote Mitt that Ann was wearing the engagement ring that Mitt had given her.

George provided regular friendship and advice to his future daughter-in-law. He patiently answered Ann’s questions about the Church of Jesus Christ of Latter-day Saints, to which she was making plans to convert. “Ann worshipped George,” remembers Richard Eyre, a campaign aide to George who became close friends with Mitt. “Mitt was gone for two and a half years. Here is his father, soon a presidential candidate, looking after her.”

Nowadays, the candidate speaks about his beacon in the incandescent terms that sons reserve for idolized fathers.

“He’s the real deal,” Mitt Romney says, his use of the present tense indicative of how his late father’s legacy lives on for him.

The lessons handed down by the mentor included everything from a near-ascetic discipline to a low-key approach for defusing skeptics’ suspicions about their religion to the political principles that would shape the younger Romney’s life.

“He has been my greatest influence,” Romney says with a soft solemnity.

A popular Michigan governor, an evolving critic of the Vietnam War and a 1968 presidential candidate who led his Republican rivals in early polls until political catastrophe struck, George Romney often brought his youngest son along while campaigning. Former advisers admit to being stunned by how much Mitt looks like their old boss, marveling over the same square jaw and the thick, swept-back hair. But the memory of their relationship is complicated nowadays in Mitt Romney’s case, because his dad was a moderate with occasionally liberal fiscal positions, and Mitt Romney is trying to convince his Republican base that he likes none of those things.

At this moment, over the telephone, he is momentarily a son making the point that he is not his father’s clone. With some of his father’s old advisers arguing that he lacks his dad’s steadfast convictions, Mitt Romney tries to turn the force of their criticism to his advantage in a bit of political jujitsu. It speaks to his campaign’s pressures, and to his skeptics’ persistent doubts about his conservative bona fides, that Romney sometimes distances himself from his father’s political philosophy.

“I’d say that my positions are not identical to those of my dad,” he explains. “I learned a lot from my dad. But I did not always agree with him.”

Nor does Romney still tout the pro-choice sentiments of his late mother, Lenore, in helping to explain the underpinnings of his own support for abortion rights during the 1990s, a position he has long since abandoned. He has settled now on an issue illustrative of a fundamental difference with his dad. “My father fought [successfully] to introduce a state income tax [to Michigan],” he says. “That’s not something I would have done. I am more conservative. But he’s the person I have admired most in political life. He’s the real deal, yes.”

* * *

A toweringly successful automobile executive who didn’t spend a year in college and was born in Mexico to Mormon parents whose family had taken refuge there, fearing religious persecution from U.S. authorities, George Romney had an early life that was everything his youngest son’s wasn’t: desperate, tough, sometimes dangerous. Early in his boyhood, the family fled Mexico in the midst of a revolution, leaving behind nearly everything they owned.

As a young adult, George Romney dreamed big. After stints as a business owner, a congressional aide and a lobbyist, he ascended into corporate boardrooms before finally winning renown as the magnate who spectacularly turned around American Motors.

By Mitt’s early teen years, his father had plunged into a newcareer in public service. Fiscally conservative but socially moderate, dedicated to forging a Republicanism that invested itself in problems of race and American inner cities, he irked conservative elements of his party. A national figure after his election as Michigan’s governor in 1962, he fought vainly for a civil rights plank in the 1964 Republican Convention platform and, afterward, refused to support the party’s nominee, Arizona Sen. Barry Goldwater, an opponent of far-reaching civil rights legislation. “My dad was a champion of civil rights when some in the Republican Party questioned the civil rights movement,” Romney proudly remembers.

As George began hobnobbing with prominent politicians and high-profile visitors such as Henry Kissinger, who saw in him a possible presidential candidate, he revealed a capacity for social adaptation that in time his two sons would emulate. Although Mormon tenets included abstaining from the use of tobacco and alcohol, “he realized that some of these guys were going out before — or after their meetings — to get a drink,” remembers G. Scott Romney, Mitt’s older brother. “He thought it just wasn’t hospitable not to give them something if they wanted it.”

Young Mitt absorbed his father’s lessons by familial osmosis. As a teenager in the Cranbrook School, the exclusive prep academy attended by many of the scions of auto executives and Michigan business leaders, his faith posed no drawback: His high school life was a charmed one and included landing a girlfriend of another faith, Ann Davies. “There’s nothing unusual [to being] around religions we’re unfamiliar with,” he recalls. “So what? So we’re not all the same.”

Meanwhile, his father continued courting political risk. Despite the opposition of many Michigan conservatives, he rammed through the state’s first personal income tax. To be free of outsiders’ pressure, George Romney had believed he needed a measure of wealth before ever getting into politics so he could act on his principles without worry about losing his income. He passed along his conviction to his two sons.

In 1966, Mitt left Brigham Young University for France to embark on a Latter-day Saints rite for young men: a long stint of missionary work.

Within the next year, his father had unofficially launched his presidential bid. The early polls made Romney the leader over longtime Republican warhorse Richard Nixon.

One issue mattered more than any other in the campaign: the Vietnam War. Romney, who had visited Vietnam in 1965 and left as a supporter of the war, signaled in 1967 that he now opposed the conflict. But he was slow to issue specifics — or a policy. Reporters began skewering his struggles to explain himself. “He was in a very difficult situation, in a battle for the presidential nomination, and trying to get his Vietnam policy right,” remembers Jonathan Moore, a former State Department official who helped verse Romney in foreign affairs.

George Romney’s national student coordinator, then-23-year-old Richard Eyre, a friend of Mitt and a devoted admirer of his father, thought that the campaign and the candidate were underprepared for the rigors of a White House campaign. Despair and racial tensions had sparked inner-city riots in Detroit and other American cities, and George had been immersing himself in understanding the causes. “The Detroit riot occurred at a time when he was supposed to get [foreign policy] briefings,” said Eyre. “George never had enough opportunity for that.”

Eventually, back at BYU, Eyre would write a master’s thesis about the campaign’s shortcomings. As he readied himself for a 2008 White House run, Mitt Romney would turn over Eyre’s main points to his own campaign team, determined not to fall prey to thesame mistakes.

“The letters that my dad wrote to me [in 1967 and 1968] about his campaign, and what I read in Rick Eyre’s thesis, made me believe that my father felt he was thrust into the limelight before he had really made a decision to run and before he was ready,” Romney says. “He became an instant front-runner. . . . Everything he did and said was scrutinized.” Romney pauses. “And bringing down the front-runner is sport.”

Political disaster hit in the late summer of 1967, even before the formal announcement of his candidacy. Two years earlier, George had traveled with other governors to South Vietnam, where he received a briefing on American military efforts there from Gen. William Westmoreland and diplomats. Now, he tried to explain on a Detroit television show why he initially supported the war. Alluding to his first trip to Southeast Asia, he remarked: “When I came back from Vietnam, I’d just had the greatest brainwashing that anybody can get.”

It was an offhanded reference to what he regarded as disingenuous government explanations. But his words, critics charged, made him look at once weak and unpatriotic.

Opponents quickly pounced. “I don’t think Governor Romney can recognize the truth when he sees it or hears it,” Defense Secretary Robert McNamara declared. Overnight, Romney went from contender to scorned laughingstock.

“We had to figure out what to do,” Moore remembers. “Some friends and aides tried to get George to take the statement back, but he wouldn’t.”

Digging in his heels, Romney took solace in the same fundamental principle that he had long preached to his two sons: Being financially independent and morally committed, he could remain true to his beliefs.

But his campaign never recovered, with Richard Nixon going on to win the nomination and the White House.

The vanquished candidate wrote a letter about the campaign’s last days to Mitt, who read and re-read it. Even now, the normally guarded Romney is open about the anger he still feels toward those who mocked his father.

* * *

George Romney’s former aides, resentful to this day of their boss’s derailment, wonder aloud how much it affected the political style of his youngest son. Walter DeVries, a prominent adviser, views the younger Romney as something of a casualty from 1968: “Mitt is gun-shy from what they did to his father. ”

DeVries added in an e-mail: “There was [a] significant difference between Mitt and his father — Mitt’s inability or unwillingness to take chances. . . . Mitt did, of course, take a huge, unpredictable risk in his [Massachusetts] health-care program. . . . But, today, Mitt is totally predictable. He will always take the perceived safe answer or course.”

It is a perspective shared among several of his father’s former advisers. “George got into real trouble with his candor, contributing to the failure of his campaign,” Moore says. “Mitt has gotten into trouble because he has been inconsistent at points and failed to demonstrate that he has core principles.”

Resistant to psychoanalyzing, Romney says that his own travails, not his father’s, have shaped his political style. But he acknowledges that events have bred caution in him. “My experience has taught me you have to exercise care,” he says, recalling a seminal moment during his leadership of Salt Lake City’s 2002 Winter Olympics. “After 9/11, I got a question about whether the Games would be canceled if another terrorist incident occurred. . . . I could see the headline: ‘Romney May Consider Canceling the Games.’ . . . So I knew I couldn’t answer the question directly. I said that it would be ‘unthinkable’ to cancel the Games.”

Yet he dismisses the effect of his father’s “brainwashing” episode. “My father later did not look back,” he says. “It was not a big issue in our house.”

Some old friends and associates of both men express appreciation for the difference between the two Romneys. “I think Mitt is cautious in the way a politician needs to be,” Eyre said.

By the early 1970s, Mitt, a student in Harvard’s law and business schools, was carrying his father’s old briefcase in what friends regarded as a silent tribute. The reverence ran both ways.

Two decades later, after Mitt had co-founded Bain Capital and amassed a fortune, his father urged him to run for the Massachusetts Senate seat occupied by the seemingly invincible Edward M. Kennedy. In a reminder of his father’s approach, the fledgling candidate encouraged aides and friends at barbecues to help themselves to a beer.

Romney lost, but about the same time Scott Romney witnessed a private moment that he believed spoke to his brother’s arrival in a new place. His father referred to his brother’s leadership at Bain and the Olympics before observing, “Mitt, you’ve had many more critical decisions to make in business than I ever did.” Scott believed his father was saying something more: “In many ways, Mitt is far more prepared to lead than my dad was. . . . My dad felt the same way.”

Such praise, of course, does nothing to allay the doubts of conservatives long leery of any Romney. Four years ago, when he cast his Massachusetts health-care plan as an exercise in common sense and personal responsibility, Romney proudly told his listeners that his father would have backed it. But his references to Massachusetts health care, and to the famously moderate Romney, are fewer this time. He still says, with no small emotion, that he learned critical decision-making skills from his father. He still says, “He’s the real deal.” Except nowadays, he is careful to add: “But we were different on some things.” He thinks his father would understand.