Peter Bergen is CNN's national security analyst, a vice president at New America and a professor at Arizona State University. He is the author of " United States of Jihad: Investigating America's Homegrown Terrorists ."

One is the son of a multimillionaire real estate developer from New York City who avoided service in Vietnam and whose experience and knowledge of the military and the national security realm are close to zero.

The other is a retired three-star general -- one of nine children who grew up in a small house in Middletown, Rhode Island. He went on to run intelligence for the US Joint Special Operations Command, which includes SEAL Team 6 and Delta Force. Later he commanded the Defense Intelligence Agency, the US military's overall intelligence organization.

But riding on a wave of ultranationalistic rhetoric, Donald Trump and his top adviser on national security, retired US Army Lt. Gen. Michael Flynn, have now catapulted from political outsiders to the White House.

Last Friday, Trump appointed Flynn as one of five vice chairs of his transition team. On Thursday, Trump offered Flynn the role of national security advisor, a transition official told CNN.

Flynn's advice to the President-elect is all the more important because he is the only person on Trump's team with any significant experience in America's post-9/11 wars that continue to grind on in Afghanistan, Iraq, Libya, Pakistan, Somalia, Syria and Yemen.

Insiders spurned Trump

Compounding Flynn's importance to the Trump national security team, more than 100 top Republican national security insiders earlier this year publicly signe d two separate letters that warned that Trump would be "the most reckless president in American history" and charging that he lacked "the character, values, and experience to be president."

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The Republican insiders who took a public stand against Trump included Gen. Michael Hayden, the CIA director under President George W. Bush; Fran Townsend, Bush's top counterterrorism adviser, Michael Chertoff, Bush's secretary of homeland security; and Meghan O'Sullivan, Bush's top Iraq adviser.

Since Trump is not quick to forgive the merest of slights it's hard to imagine him calling on any of the officials who have publicly taken a stand against him to serve in key national security slots.

To be sure, earlier this year, Trump did receive the endorsement of 88 retired general and admirals.

But according to CNN military analyst, retired Lt. Gen. Mark Hertling, who was one of the top American generals in Iraq from 2007 to 2008, the flag officers who signed the letter of support for Trump were largely those without any experience of the war against al Qaeda and its allies.

"I didn't recognize many of those names as being there in the fight with me over the last 16 years," Hertling told CNN when the flag officers endorsed Trump in September.

Which bring us back to Flynn, who not only is an enthusiastic public booster of Trump, but also has serious credentials in the fight against al Qaeda in Iraq -- the parent organization of ISIS -- because he ran the intelligence operations that helped put al Qaeda on the run in that country in 2007.

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Half a decade later, Flynn was the general in charge of the Defense Intelligence Agency (DIA). When Flynn was the DIA director he warned of the rise of what would become ISIS.

Flynn debuted on the public stage when he made a fiery speech of support for Trump at the Republican convention in July charging that President Obama and Hillary Clinton had betrayed the ideals of their country and even led the crowd in chants of "Lock her up!"

Generals who had served with Flynn were puzzled at this performance, which went against their code to not take such clearly partisan positions, even in retirement. So too had retired Gen. John Allen, who gave his own stem-winding speech in support of Hillary Clinton at the Democratic convention.

The former chairman of the Joint Chiefs, Martin Dempsey, went public with his critique of Flynn and Allen in a letter t o the Washington Post in July.

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A registered Democrat, Flynn became a vocal critic of the Obama administration after he was forced out of his DIA post in 2014. Flynn had pushed for more DIA personnel to serve in the war zones rather than at DIA headquarters in Washington. This was an excellent idea but it ruffled bureaucratic feathers at DIA, which may have played a part in being Flynn ousted.

In his book, Flynn says his removal came because he testified in 2014 before a congressional committee that the jihadist terrorist threat was growing, not declining, as was the official Obama administration line at the time. Flynn, of course, was right about the growing threat.

Flynn's worldview

Given the key role that Flynn has already played for Trump and the role going forward that he will likely play during the Trump presidency, what are his views on national security and foreign policy in general?

Trump himself has not laid out a clear agenda on the national security issues that are the most pressing for the United States, from the resurgence of the Taliban in Afghanistan; to the deepening Syrian civil war; to the fight against ISIS in Iraq and Syria and the flexing of Russian muscles under President Vladimir Putin.

Luckily, there are some answers to Flynn's views in a book he published in July, "Field of Fight: How We Can Win the War Against Radical Islam."

Flynn claims that the United States is in a "world war" with radical Islam, a war that "we're losing" that could last 'several generations." He also asserts that "political correctness forbids us to denounce radical Islamists."

American Islamists, Flynn claims, are trying to create "an Islamic state right here at home" by pushing to "gain legal standing for Sharia." Flynn cited no evidence for this claim.

In particular, Flynn portrays Iran as the source of many of America's national security problems. Flynn co-wrote his book with Michael Ledeen, a neoconservative academic who has long been a bitter critic of the Iranian regime.

Flynn advocates the American overthrow of regimes that are "Islamic republics" which could include not only Iran, but also American allies such as the Islamic Republic of Afghanistan and the Islamic Republic of Pakistan.

Flynn's views, in short, align closely with Trump's and in some cases are more extreme, since not even Trump is advocating regime change in Iran, Afghanistan and Pakistan.

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Flynn advocates going after the "violent Islamists wherever they are," which doesn't sound much different than what the Obama administration is already doing, given that it is conducting various forms of warfare in seven Muslim countries.

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Meanwhile, the Iraqi army backed by US airstrikes is fighting in the streets of Mosul, the second largest city in Iraq, where ISIS declared its so-called caliphate two years ago.

Flynn, like Trump, sees Russian president Vladimir Putin as someone the US can do business with. In December, Flynn attended a banquet in Moscow where he sat next to Putin . He also has appeared on the Kremlin TV mouthpiece, Russia Today (which Flynn has compared to CNN).

If Flynn is Trump's national security advisor, we can expect him to push for a closer relationship with the Russians; a punitive policy on Iran -- and a more aggressive war on Islamist militants around the world. These views mesh well with what we have heard from Donald Trump on the campaign trail.

Such new policies, however, come with real risks: Warmer relations with the Russians might encourage Putin's adventurism in Eastern Europe; getting tough with the Iranians might derail the deal that prevents Iran from developing nuclear weapons -- and widening the war against Islamist militants could be expensive in blood and treasure.