Retired Lt. Gen Michael Flynn gestures as he arrives at Trump Tower, Thursday, Nov. 17, 2016, in New York. (AP Photo/Carolyn Kaster)
Retired Lt. Gen Michael Flynn gestures as he arrives at Trump Tower, Thursday, Nov. 17, 2016, in New York. (AP Photo/Carolyn Kaster)

The most influential national security job in the still-forming Trump administration has been offered to a retired three-star general who helped dismantle insurgent networks in Afghanistan and Iraq but then surprised — and sometimes dismayed — colleagues by joining the political insurgency led by Donald Trump.

As national security adviser to Trump, retired Lt. Gen. Michael Flynn would be responsible for helping a president with no national security experience navigate complicated global issues including the unfinished campaign against the Islamic State, the expansionist agenda of China and rising aggression from Russia. Flynn’s selection for the post was confirmed Thursday night by a person close to the Trump transition team who spoke on the condition of anonymity to discuss internal conversations.

As a decorated military intelligence officer and former head of the Defense Intelligence Agency, Flynn has deep experience to draw upon as he serves as Trump’s principal point of contact with the State Department, the Pentagon and a collection of U.S. intelligence agencies that have surged in power and influence since the Sept. 11, 2001, attacks.

“This is a guy who has the president’s trust, has credentials with the military, credentials with the intelligence community and credibility with Congress,” said Rep. Devin Nunes, R-Calif., the chairman of the House Intelligence Committee and a member of the Trump transition team. “He’s a very serious person. He takes his job very seriously.”

But Flynn has also shown an erratic streak since leaving government that is likely to make his elevation disconcerting even to the flag officers and senior intelligence officials who once considered him a peer.

Flynn stunned former colleagues when he traveled to Moscow last year to appear alongside Russian President Vladimir Putin at a lavish gala for the Kremlin-run propaganda channel RT, a trip Flynn admitted he was paid to make and defended by saying he saw no distinction between RT and U.S. news channels such as CNN.

Flynn said he used the trip to press Putin’s government to behave more responsibly in international affairs. Former U.S. officials said Flynn, seen dining next to Putin in photos published by Russian propaganda outlets, was used as a prop by the autocratic leader.

Flynn was forced out of his job as director of the Defense Intelligence Agency in 2014 over concerns about his leadership style.

Spurning the decorum traditionally expected of retired U.S. flag officers, Flynn became a fervent campaigner for Trump and was given a high-profile role speaking before the GOP convention, an appearance in which he led the crowd in “lock her up” chants against Democratic nominee Hillary Clinton.

Flynn’s behavior drew the ire of former colleagues and superiors, including retired Gen. Stanley McChrystal, who made Flynn his top intelligence officer during critical stretches of the wars in Afghanistan and Iraq.

McChrystal and retired Adm. Michael Mullen, former chairman of the Joint Chiefs of Staff, contacted Flynn and urged him to show more restraint, with Mullen warning that Flynn’s behavior could jeopardize White House trust in the military.

Flynn dismissed those concerns in an interview with The Washington Post earlier this year, saying efforts to quiet him impinged on his free speech rights.

A longtime Democrat and native of Rhode Island who grew up in a military family, Flynn has articulated an increasingly dark vision of the direction of the United States, saying that it has fallen into a struggle between “centrist nationalists” and “socialists.”

He has also warned that the United States is failing to adequately address the threat posed by what he calls a “diseased component” of Islam. “There’s something going on in the Muslim world,” he said. “Why do we have heightened security at our airports? It’s not because the Catholic Church is falling apart.”

That view, and his willingness to voice it publicly, put him in close alignment with Trump, who has called for Muslims in the United States to be registered, subjected to loyalty tests and in some cases deported.