(CNN) In his commencement speech at the Coast Guard Academy on Wednesday, President Trump proclaimed that "no politician in history, and I say this with great surety, has been treated worse or more unfairly" by the media.

That's probably all you saw -- or heard -- about Trump's speech. But, lucky for us, the camera kept rolling -- and the microphones stayed live. (And CNN's Joe Von Kanel kept listening.)

DHS chief caught on hot mic jokingly telling Trump to use his new ceremonial Coast Guard saber on the press https://t.co/pQcjGf4Wtj pic.twitter.com/FuVhABr4z5 — CNN (@CNN) May 17, 2017

That's Department of Homeland Security Secretary John Kelly sitting next to Trump. And it's Kelly who says to Trump of the sword: "Use that on the press, sir."

Memo to all politicians: You should assume: