The exchanges with Flake, and then McCain and Kyl, weren't the candidate's first experience with the kind of deeply partisan controversy that threatens his All-American, last-action hero brand.
After leaving the Bush administration following nearly four years as surgeon general, he accused the administration's political appointees of stifling science in the health sphere. He testified before a congressional committee that officials had delayed and watered down his damning report on second-hand smoke and forbidden him from speaking about or releasing studies on stem cells, the morning-after pill, and sex education. Carmona also accused officials of advising him not to attend the Special Olympics because of the organization's ties to the Kennedy family.
Carmona says he's maintained good relationships with Republicans since then. His testimony wasn't about payback, he explains, and that he was simply answering the questions put before him. He notes that he sought counsel from senior GOP senators before entering the 2012 race.
Perhaps more importantly, he's received endorsements from a number of high-profile and popular figures. Astronaut Mark Kelly, husband of former Rep. Gabrielle Giffords, D-Ariz., is a prominent supporter and fundraiser. Carmona also has the endorsement of former President Bill Clinton, the most popular character in the Democratic Party.
And then there's President Obama.
"We had a nice conversation," Carmona said told ABC News in February, "and he did urge me to consider running, because he felt that we needed new blood in Washington."
Also on Carmona's side: his position in immigration reform.
Ever since Gov. Jan Brewer signed the SB 1070 Arizona immigration law, the issue has dominated the state's politics. Democrats think that could be a boon, and have used it to motivate the law's opponents to volunteer and vote. The Obama campaign had also included Arizona in its early swing state plans, thanks largely to a riled-up Latino base, though they have long since conceded the state to Mitt Romney.
Flake, meanwhile, has turned hard to the right, after he co-authored a major immigration reform bill with Democratic Rep. Luis Gutierrez (D-Ill.). Their bill contained the same broad strokes as the reform push undertaken in 2007 by Sens. John McCain and Ted Kennedy. Flake has since abandoned the comprehensive approach, making the same turn McCain did before his Senate reelection campaign in 2010.
"I've been down that road, and it is a dead end," Flake said in March 2011. "The political realities in Washington are such that a comprehensive solution is not possible, or even desirable given the current leadership. Border security must be addressed before other reforms are tackled."
Carmona supports the broad strokes of comprehensive reform -- enhanced border security and a pathway to some form of permanent residency -- thereby setting up a campaign in which Flake runs against his own former policies and Carmona touts the general outline of Flake's own bill.
Immigration, it so happens, is part of the reason Carmona is running as a Democrat.
"I couldn't buy into the value proposition that some of the Republicans were touting," Carmona told ABC, speaking about the GOP tendency to rally around deportation – Mitt Romney has suggested a short-term policy that encourages immigrants to "self-deport" -- and loudly decry the large population of illegal immigrants in the U.S.
Despite it all – decades of adventure and triumph, his unique political course, and plenty of money spent to tell the story -- overcoming Flake and Arizona's heavy Republican bent could still prove a bridge too far.
Arizona has only elected one new Democratic Senator – Dennis DeConcini in 1976 – since Carl Hayden retired in 1962 after 36 years in office. DeConcini left the Senate to join the board of Freddie Mac in 1995. Since then, Kyl and Sen. John McCain, who was first elected in 1986, have run and won six elections without a serious Democratic challenge.
Gov. Brewer, a leading architect of that controversial immigration law and author of "Scorpions for Breakfast, once infamously confronted President Obama on a airport tarmac in what she called a "terrible encounter." The state has only elected one Democratic governor since Raul Hector Castro in 1974.
If Carmona can break through, he will likely have Flake, whose conservative, anti-spending platform has never been put under the statewide spotlight, to thank. Not that at anyone should be surprised to see Richard Carmona get what he's after. History in Arizona today would be worth little more than a chapter in the final account his improbable life.