Michael Flynn, a former lieutenant general in the Army, became the third high profile official to be nominated on Friday following Sen. Jeff Sessions and Rep. Mike Pompeo. It sets up the war veteran to become a prime player on the president’s foreign policy team, creating an interesting outlook for the future of U.S. involvement in the Middle East.

His appointment for the national security advisor role — which he will reportedly accept — follows time spent as the Defense Intelligence Agency’s top official under President Obama.

Flynn, a registered Democrat, has been highly critical of Obama since leaving that position in 2014. His early efforts to advise fellow Washington outsider Donald Trump on national security paid dividends on Friday, when Trump wrote that  “General Flynn is one of the country’s foremost experts on military and intelligence matters and he will be an invaluable asset to me and my administration.”

Here are five things to know about Lt. Gen. Michael Flynn:

He has championed an aggressive assault on radical Islamic terrorism

Flynn’s tours of duty on the battlefield include deployment for the Grenada invasion, and eventually a leadership role commanding the 111th Military Intelligence Brigade and director of intelligence for Joint Special Operations Command.

According to Stars and Stripes, the official newspaper for military personnel, Flynn believes American policy has been “too soft on terrorism” and pins the Islam faith as a “political ideology” and proponent of extremism. In his 2016 books he cites these beliefs as being the reason he was forced to step down from his position as director of the DIA.

He is one of the military’s highest profile members to criticize Obama Administration policy

Flynn has received mixed reviews for how quickly his involvement, and eventual criticism, came to Washington politics following his departure of the military. He told Foreign Policy that it stems from a responsibility to his family, saying, “The people in the United States have lost respect and confidence in their government to be able to solve the problems that we face now and in the future… That’s not a good place to be.”

Other military leaders are unsure about his unorthodox approach.

Following Flynn’s speech at the RNC, retired Gen. Martin Dempsey told the Washington Post that the military “is not a political prize,” and that “the American people should not wonder where their military leaders draw the line between military advice and political preference.”

However, Flynn does have his fans within the military. One anonymous intelligence officer put it this way: “It’s a form of moral courage that he does speak up — and always has throughout his career — when he thinks mistakes are going to be made.”

He believes in working with Russia to defeat terrorist threats

In a move that was sure to please his new boss, Flynn took to the media to promote working with Russia in order to defeat radical Islamic terrorism over the course of the campaign.

Not only did he work for Russia’s state-owned TV network Russia Today, but according to the New York Times Flynn attended a gala for the network and made sure to rub elbows with President Putin at that time.

Breitbart, run previously by Trump’s chief strategist Steve Bannon, laid out Flynn’s work this way: With the election of Mr. Trump, the old way of combatting terrorism in defining states as the battlefield will give way to one in which the Muslim religion will be targeted in and of itself.

It’s in this way he places Russia as a key partner in reversing a “collective frustration” over the post-2011 war effort, and finishing off ISIS as they are pushed out of Iraq.