Now Washburne has formally joined an intelligence panel chosen by the president that has access to some of America's most closely held secrets and a line to the Oval Office.
Past presidents have often named political supporters to the board, which one political scientist compared to the controversial yet common practice of presidents doling out plum ambassadorships to partisan patrons, and Trump's board does include other members with deep national security experience.
But former PIAB chairman and ex-Republican senator Chuck Hagel said that considering the sensitive nature of the organization -- and its broad access to secrets -- the practice of pulling from political supporters to fill out the ranks is a particularly concerning tradition.
"From that standpoint it does bother me," said Hagel, who presided over then-President Barack Obama's PIAB from 2009 until he was named defense secretary in late 2013. "But it's been done for many years, I mean both administrations. No one is really very pure in that."
For his part, Washburne acknowledges he does not have a national security background like some others on Trump's board, some of whom served decades in the CIA, for instance. But he said that he did not believe his appointment had anything to do with his past political or financial support to the president or the Republican party.
Instead, he said it was the 20-odd months he recently served the head of the government's Overseas Private Investment Corporation – another Trump appointment in June 2017 – that gave him enough experience with "economic intelligence" to make him a valuable member of board.
"I was in a [secure facility] every day reading intelligence briefings on countries and leaders and businesspeople throughout the world, because we do business in every far, dark corner of the world," Washburne told ABC News in late May, shortly after the White House announced Trump's intention to nominate him, but before he passed the additional security checks to formally join the board. "So what expertise I bring to the board is something that none of the others there have and wouldn't have because they're not dealing with economic issues. … When we talk about intelligence gathering, it's not just military capabilities, it's economics as well."
The PIAB is an unpaid, part-time panel made up of private citizens that was created in 1956 by then-President Dwight Eisenhower to provide an independent perspective on the way the U.S. intelligence community goes about its normally cloistered business. At least twice a year it's supposed to provide assessments about the "quality, quantity, and adequacy of intelligence activities," along with the "effectiveness" of the intelligence community's structure and performance, according to the White House.
The board's specific work is kept secret – though a recent government report revealed Trump's board has met with the intelligence community inspectors general at least twice to discuss ways to protect classified information.
And while those who have studied or served on the board say it's only as useful as the president allows it to be, the White House website says the board "has had immense and long-lasting impacts on the structure, management, and operations of U.S. intelligence."
Several members of the board did not respond to requests for comment for this report or referred ABC News to the White House National Security Council. The council declined to comment on the board's activities or the criteria for its membership under Trump.
From a CIA legend to big-money investors
From its founding early in the Cold War, the makeup of the PIAB has been a "balance between real intelligence experts and people with other experience not directly related to intelligence but who offer a useful broad-level view," according to Michael Desch, a political science professor at Notre Dame who co-authored the book "Privileged and Confidential: The Secret History of the President's Intelligence Advisory Board."
Desch's book surveyed all the boards from the Eisenhower administration to the first half of the Obama administration, including how politics can creep into what was originally supposed to be a non-partisan panel.
Trump's board got a late start in his administration but has grown over the past year and a half in a series of spare press releases and notices posted on the White House website to 14 members as of mid-August. Their respective national security experiences vary significantly.
On one end, the board includes some former CIA officers who spent their careers in the intelligence world, including Agency legend Charles Allen and current Fox News contributor Daniel Hoffman. Newer PIAB member Gen. Michael Hagee (ret.) served in the U.S. Marine Corps for more than 30 years and served as commandant before retiring.
Others had government experience during prior administrations that involved national security, like ex-Senate Intelligence Committee Chairman Saxby Chambliss and the board's No. 2, Samantha Ravich, who was deputy national security advisor to ex-Vice President Dick Cheney.
Then there are four members of the board, including Washburne, whose public biographies show long careers in business but relatively scant professional experience in government or national security positions.
And while half of the PIAB members supported Republican candidates or organizations with financial donations ahead of the 2016 election, some with relatively small donations of a few thousand dollars, those four members donated by far the most among the board members -- more than $100,000 each, according to Federal Election Commission data.
The New York financier in charge
The board's chairman, New York investor Stephen Feinberg, donated nearly $1 million to a pro-Trump super PAC just days before the 2016 election, only the latest installment of large gifts in support of Republican candidates or organizations in the 2016 cycle. He had previously donated some $200,000 to a pro-Jeb Bush super PAC.
Feinberg, whose investment firm's portfolio includes the defense contractor DynCorp, was named by Trump to lead the intelligence board in May 2018, a year after reports surfaced that Trump was considering naming him to some other special position in the administration to review the intelligence community in the shadow of the president's claim of an anti-Trump "deep state."
Sen. Susan Collins, R-Maine, brought up the prospect in a congressional hearing in February 2017, saying that, "As far as I can tell, this individual does not have national security experience, nor does he appear to have experience in intelligence."
The point of the hearing was to consider former Sen. Dan Coats for the job of the Director of National Intelligence – a job he recently left. At the time Coats said that while he disagreed with the idea of Feinberg being placed in a new, special position, he said he knew Feinberg "personally" and considered him a "patriot [who] wants to serve his country and […] brings many talents to that."
This February, months before Coats' departure, the Office of the Director of National Intelligence told ABC News in a statement, "Director Coats supports Stephen Feinberg's leadership of the PIAB and the ODNI is working with the PIAB to improve the effectiveness of our nation's intelligence capabilities."
A spokesperson for Feinberg's investment firm, Cerberus Capital Management, declined to make Feinberg available for comment for this report.
A 'student' of national security
After Feinberg and Washburne, the two other major political donors with lighter national security experience on the PIAB are Goldman Sachs management executive James Donovan and California investor John Hurley, each of whom in 2015 and 2016 gave over $100,000 to Republican organizations and approximately $100,000 to a pro-Jeb Bush organization. Neither appears to have made major donations to organizations that were directly pro-Trump.
Donovan, who was previously nominated for a top position at the Treasury Department but withdrew, did not respond to requests for comment for this report. A spokesperson for Goldman Sachs declined to comment.
An online biography for Hurley at Stanford Graduate School for Business where he lectures in finance says he's associated with a handful of national-security and foreign policy-related think tanks, and he served five years in the U.S. Army, including in the Gulf War in the early 1990s. A spokesperson at Hurley's investment firm directed ABC News' questions to the White House National Security Council.
But Hurley has the backing of another national security heavy-hitter, former Chief of Staff of the U.S. Air Force Gen. Norton Schwartz (ret.). Schwartz is the president of an organization called Business Executives for National Security, where Hurley is on the Board of Directors.
"I think he's a high-quality fella and who I think cares about national security and is a student of it," Schwartz told ABC News in February after the White House announced its intention to appoint Hurley. "He is smart, and, in my experience, he has demonstrated exceptional judgment ... [and] in the end I think all of us make our way based on the quality of our judgment.
"I think he'll fit fine," said Schwartz.
Another member of the board, the newest addition, is J. Tucker Bailey, a cybersecurity specialist and partner at the global consulting firm McKinsey & Company. His online biography says he is a former Navy officer and was a special agent with the Naval Criminal Investigative Service (NCIS). He does not appear to have made significant political contributions in the 2016 election cycle.
Outside the 'echo chamber'
Desch said that historically speaking, Trump's board is "not the best" he's studied – an honor he bestows only on Eisenhower's original board -- because of what he said appeared to be the small number of political appointments, but he "would not put it in the Looney Tunes land of boards that have been appointed" by other presidents either.
Going back decades, one of the worst, Desch said, was convened by President Richard Nixon. While not short on experts, the board was aggressively partisan in its work, he said.
Former President Barack Obama at times placed some political supporters with thin intelligence backgrounds on his advisory board, Desch said.
He said that Obama's PIAB "started out strong" under the bipartisan leadership of Hagel, a former Republican senator, and co-chairman David Boren, a former Democratic senator. Hagel told ABC News that they cautioned the president about appointing unqualified members to the board.
"If he was interested in a show kind of place, a big repository for big donors, we said, 'Don't send them our way, we really won't accept them,'" Hagel said.
But Desch said that following a reportedly dramatic shake-up in Obama's board in 2014, most of the board was dismissed and newcomers included a few people with "far less seemingly relevant experience." For example, one of the new members, Chicago investor Jim Crown, had been a major political donor and worked on Obama's 2008 campaign, according to federal data and contemporaneous news reports. Crown did not respond to a request for comment for this report.
ABC News also previously reported how a prolific Democratic donor was appointed to a similar body, the International Security Advisory Board, which advised the State Department, at the time led by Secretary of State Hillary Clinton.
Hagel said that appointing people with relatively little background in national security is not necessarily a problem -- after all the PIAB is designed to offer a view from private individuals who don't have ingrained ideas about how the nation's many spy agencies should work.
"You wouldn't want to restrict the membership just to the echo chamber," Hagel said. "We get a hell of a lot of that already in Washington. … I think there is some benefit, no question, of having outside people come in."
It's only an issue, according to Desch, when people are appointed who aren't serious about the work, who "you know, just want the White House pass."
When ABC News asked Sen. Mark Warner, the Democratic vice-chairman of the U.S. Senate Select Committee on Intelligence, if he had any concerns about the makeup of the current board and, by extension, the kind of advice the president might be getting, Warner said only that the board "can be an effective entity to provide independent advice to the President on the functioning of the Intelligence Community."
"It should be filled with members who bring unique perspective to national security and how intelligence can operate most effectively," he said in a statement in July.
Potential conflicts of interest, so far a 'theoretical concern'
The Washington Post reported that critics of Feinberg's appointment were concerned at the time about potential conflict of interest, citing in part his firm's ownership of Dyncorp, which does a significant amount of government business. In its report, the Post cited a source that said Feinberg divested his interest in Cerberus' holdings that involved defense or intelligence issues.
Desch said concerns over potential conflict of interest when it comes to private businesspeople handling classified intelligence are as old as the board itself, since the members may have investments or other interests that could be affected by what they learn or what the board recommends to the president.
But Desch said he's unaware of any members abusing their access and said that the setup of the board, including the use of staff members on loan from various government agencies, would make such abuse unlikely.
Desch said that as far as he knows, it remains a "theoretical concern."
Perhaps more valuable to the members, he said, are the connections that come from being on the board itself.
Top intelligence officials are going to return phone calls from a member of the President's Intelligence Advisory Board, Desch said, "That's for sure."