Yep, came as a surprise to me, I have to admit.
Also of note:
But Mattis quickly moved on from the jokes and picked up a more serious tone, citing a speech that Abraham Lincoln gave in 1838 to the Young Men's Lyceum of Springfield, Ill.
In it, Lincoln "observed great nations crumble for one of two reasons," the first being foreign invasion, Mattis said, which the future president dismissed as "inconceivable."
The second, he said, paraphrasing Lincoln, "was corrosion from within – the rot, the viciousness, the lassitude, the ignorance."
"Anarchy is one potential consequence of all this. The other is the rise of an ambitious leader, unfettered by conscience, or precedent or decency, who would make himself supreme," he said.