Former GOP House Speaker Newt Gingrich published an op-ed this week defending embattled National Security Adviser H.R. McMaster.

Gingrich, a Fox News contributor, said he has known McMaster since he was a captain in the Gulf War, and he described him as a brilliant battlefield commander.

But it is McMaster’s moves inside the NSC that have come under scrutiny — the pushing out of a number of loyalists from Trump’s campaign.

He first pushed out Deputy National Security Adviser K.T. McFarland in April, and then quietly replaced several other officials.

Starting in late July, he ousted three senior NSC officials who were trying to implement the president’s “America First” foreign policy agenda — Rich Higgins, Derek Harvey, and Ezra Cohen-Watnick.

Gingrich defended McMaster’s credentials, writing, “The truth is, McMaster understands three things that his critics do not.”

“First, the American system of national security is extraordinarily complex,” Gingrich said, citing Trump’s summit in Riyadh where “more than 55 Arab and Muslim countries came together to work toward defeating terrorism in the Middle East.”

Ironically, a source close to Harvey told Breitbart News earlier this week that McMaster had actually opposed the idea of the summit because it was “too ambitious,” and he had wanted to scale it back.

Gingrich also praised McMaster for his “firsthand experiences in Iraq and Afghanistan,” and for “innovative thought, creative solutions, and institutional and cultural change in our national security systems.”

However, McMaster’s support for a plan to send 3,000 to 4,000 more U.S. troops to Afghanistan to hit the Taliban harder and drive back them to the negotiating table has been panned by some experts as doing more of the same.

“He is the right person, in the right place, at the right time,” wrote Gingrich. “We are fortunate to have him serving the country.”