Chief of staff John Kelly took to the podium in the White House press briefing room yesterday just after 3 p.m. What ensued was the most stunning 12 minutes in that room in long memory.

He educated. He excoriated. He earned the respect of America yet again.

He was there to set the record straight about President Trump’s condolence phone call to the widow of Army Sgt. La David Johnson, who died in a terrorist attack in Niger on Oct. 4.

Congresswoman Frederica Wilson, a Florida Democrat, listened in on the call and loudly claimed that Trump had insulted the mourning family by saying Johnson “knew what he signed up for.”

The beltway media ran with the story and a firestorm erupted. Wilson has gladly been soaking up the attention her wild claims about a grieving family have garnered.

Kelly came to extinguish the fire and he held nothing back. He wasn’t running defense for the president. This was much bigger than that. This was personal.

“Most Americans don’t know what happens when we lose one of our soldiers … in combat,” Kelly said. “Let me tell you what happens. … Their buddies wrap them up in whatever passes as a shroud, put them on a helicopter …

“Their first stop along the way is when they’re packed in ice … and flown to Dover Air Force Base, where Dover takes care of the remains, embalms them, meticulously dresses them in their uniform with the medals that they’ve earned, the emblems of their service and then puts them on another airplane … that takes them home.”

In a room whose walls generally endure ricocheting rhetoric, artful spin, and crafty doublespeak, the weight of Gen. Kelly’s serious words seemed to stun everyone present.

He said he recommended to Trump that he avoid calling the families of fallen soldiers but the president insisted. He asked Kelly what to say and the retired Marine choked up as he recalled what the casualty officer said to him when his son perished.

“He was doing exactly what he wanted to do when he was killed,” Kelly said. “He knew what he was getting into by joining that 1?percent. He knew what the possibilities were because we’re at war … When he died he was surrounded by the best men on this earth, his friends. That’s what the president tried to say to four families the other day.”

John Kelly was magnificent yesterday. He defended the sacred pillars of America without agenda, criticizing opportunist politicians, the media and even, perhaps, the president himself, for his treatment of a Gold Star family at the Democratic National Convention.

Afterward, Fox News White House correspondent Kevin Corke tweeted, “I’ve covered 3 administrations as a WH Correspondent. Never seen anything like today’s briefing. Riveting, powerful and sadly necessary.”

Corke later told me that Kelly “proved that the ultimate trump card is the unvarnished, painful reflection of a parent who has lost a child at war.”

As it should be.