Former Massachusetts Gov. Mitt Romney speaks during his final campaign rally at Verizon Wireless Arena on November 5, 2012 in Manchester, N.H. (Justin Sullivan/GETTY IMAGES)

Mitt Romney wasn’t always sold on running for the White House a second time, according to a soon-to-be-released book about the 2012 presidential campaign by The Washington Post’s Dan Balz. The book details the Republican’s early opposition to the idea and his later consideration of pulling the plug on his nascent bid.

In the exploratory phase of his campaign in May 2011, Romney was preparing one morning to deliver a speech in Michigan to defend the health-care plan he signed into law as governor of Massachusetts and to attack President Obama’s health-care law. The Wall Street Journal released a scathing op-ed that day criticizing Romney for his Massachusetts plan.

Romney’s eldest son received a message from his father early that day, he told Balz. “ ‘I’m going to tell them I’m out,’ ” Tagg Romney recalled his father saying. “He said there’s no path to win the nomination.”

Romney confirmed after the election that he called his son one morning to tell him he thought he wasn’t going to run. “I recognized that by virtue of the realities of my circumstances, there were some drawbacks to my candidacy for a lot of Republican voters,” he told Balz. “One, because I had a health-care plan in Massachusetts that had been copied in some respects by the president, that I would be tainted by that feature. I also realized that being a person of wealth, I would be pilloried by the president as someone who, if you use the term of the day, was in the ‘1 percent.’ ”

Romney’s exchange with his son wasn’t the first time he expressed doubts about running. During a Christmas holiday trip to Hawaii in 2010, the Romney family held a vote. Should Romney, who lost the 2008 presidential primary, run again? Ten of 12 family members voted no — including the candidate. Only Tagg and Ann Romney, Romney’s wife, voted yes.

The book, titled “Collision 2012: Obama vs. Romney and the Future of Elections in America,” is due out Aug. 6. It details the 2012 White House race through Election Day and its aftermath.

One part of the story involves New Jersey Gov. Chris Christie, whom some Republican power brokers had tried to woo into the race. Christie described the effort to recruit him as “craziness.” He recalled being courted by high-profile Republicans, including former secretary of state Henry Kissinger.

At one point, wealthy New Yorker Ken Langone invited Christie to a breakfast, the governor recalled. “The way he sold it to me was that this was going to be a small group of his friends who were going to sit and talk with me about why I needed to do this for our country,” the governor said. When Christie showed up, he was surprised to see what he estimated to be 60 people at the gathering.

Christie was later considered by the Romney campaign as a potential vice presidential running mate. A Romney adviser told Balz that the campaign never found a satisfactory solution to a Securities and Exchange Commission “pay to play” rule that would have complicated fundraising efforts had Christie been tapped for the ticket. The SEC rule would have presented Romney with a quandary in soliciting contributions from Wall Street, given Christie’s status as governor of New Jersey.

Balz also spoke with Texas Gov. Rick Perry, a Romney primary opponent who attracted widespread attention when, during a debate, he was unable to name a third government agency he would eliminate as president.

“I told somebody the ‘oops’ moment was kind of just one of those things that happens in life and I knew I was going to see it over and over again, but it wasn’t anything,” Perry told Balz. “I think I went back and actually slept that night.”

Romney, meanwhile, opened up to Balz about his conservative stance on immigration during the campaign, and his use of the term “self-deportation,” which Democrats repeatedly criticized. Romney said he did not anticipate the blowback he would face.

“I thought of it as being a term that is used in the community of those discussing immigration,” he told Balz. “I hadn’t seen it as being a negative term.” He later added, “You have two options of dealing with those that have come here illegally: deportation or self-deportation. The president has deported more I think in four years than President Bush did in eight years. So the president was using a deportation method. The view of others is, ‘No, let people make their own choice.’ . . . So I was looking for a more, if you will, compassionate approach, which is let people make their own choice.”

Romney also reflected on his “47 percent” comment, which he said he didn’t think would become a major focus. He said the perception that his remarks suggested that he didn’t care about many Americans was incorrect.

“But I realized, look, perception is reality,” he said. “The perception is I’m saying I don’t care about 47 percent of the people or something of that nature, and that’s simply wrong.”

His campaign’s biggest mistake in the primary, Romney told Balz, was not paying more attention to the Feb. 7 contests in Colorado, Minnesota and Missouri. He also worried about Newt Gingrich’s candidacy, even as his advisers tried to assure him that the former House speaker would not win.

“I have to tell you that, in the discussions I had with my senior staff, people like Stuart Stevens and Russ Schriefer said, ‘Look, Newt is not going to be the nominee. I don’t care what the polls say, he’s not going to be the nominee.’ I was far less sanguine about that,” Romney said.