His latest book with co-author Mark Salter is "Hard Call: Great Decisions and the Extraordinary People Who Made Them." McCain and Salter examine the qualities of historic decision-making such as foresight, confidence and humility.
In the book's introduction, McCain gives little insight into his own decision-making process.
"The ways I have arrived at important decisions, both right and wrong ones, have varied over the years," McCain writes. "I hope this has resulted in a progressively better approach. But I have blundered often enough in recent years to foreswear such a boast."
McCain staked out lonely ground on the GOP presidential campaign trail with his early and vocal support of President Bush's surge strategy in Iraq and his push for bipartisan comprehensive immigration reform.
"He looks back and has some confidence that choosing the right path, or following the right policies, will win out even on occasions when at first glance it might look like a loser," says Scott Celley, a McCain Senate spokesman in the late 1980s and early 1990s.
When McCain fails to follow what he believes is right, it usually backfires.
During the 2000 campaign, McCain was asked to comment on the controversy over South Carolina's continued flying of the Confederate flag at its Capitol.
After initially acknowledging that many Americans reject the Confederate flag as an offensive "symbol of racism and slavery," McCain allowed political advisers to talk him into amending his statement to avoid offending the flag's supporters.
That political compromise still gnaws at McCain, who wound up losing to Bush in the South Carolina primary anyway.
"I had been a coward, and I had severed my interests from my country's," McCain wrote in his 2002 memoir, "Worth the Fighting For." "All my heroes, fictional and real, would have been ashamed of me."
McCain regularly taps others for advice in making political decisions.
"I have a wide circle of people that advise me," McCain said in an interview on his "No Surrender" bus tour in September.
Celley said McCain's reliance on "a multidisciplinary collection of aides" dates back years but adds that the most important factor always has been the incredibly well-read McCain himself.
"He sucks up information," Celley says. "You can overload some people on Capitol Hill and elsewhere on facts and details. You can't (overload) John McCain. He can make a decision even as he is getting new information and moving forward on a developing issue."
John McCain often finds himself crosswise with members of his own party and doesn't hesitate to seek bipartisan fixes to problems.
In the early 1990s, chastised by his own embarrassing link to the Keating Five scandal, McCain emerged as a national reformer. He not only took on the big money campaign-finance system but also free-spending congressional appropriators, the tobacco companies and others McCain felt stood in the way of his good-government agenda.
During his 2000 presidential race, McCain ran as a progressive Republican in the style of President Theodore Roosevelt, one of his personal heroes. He stressed patriotism and advocated for a muscular foreign policy.
Between then and now, terrorists crashed hijacked planes into the World Trade Center and the Pentagon. In his 2008 campaign, McCain solemnly calls "the war against Islamic extremism" the overarching challenge of the generation.