Nobody tell Trump. Just because he was there doesn't mean he understood what was happening. He only thought his presence would be enough to intimidate the justices. After a couple of recent rejections from SCOTUS in cases and his public berating of them, I guess he thought they'd get with the program if he showed up in person.On Wednesday, Donald Trump became the first sitting president to attend Supreme Court arguments in person. It must have been a brutal morning for him. The justices heard Trump v. Barbara, a challenge to the executive order purporting to strip birthright citizenship from the children of many immigrants—and it quickly shaped up to be a blowout against the administration. Seven justices expressed profound skepticism toward the government’s revisionist history of the 14th Amendment, with most sounding downright hostile toward the pseudo-originalist theory cooked up to legitimize the policy. Only Justices Clarence Thomas and Sanuel Alito asked questions friendly to the administration, and none of their colleagues sounded persuaded by their strained defenses.
Slate
In the Godfather movies, there was a scene in a trial where one of the mafia members was about to rat on the stand, and Michael Corleone had the guy's brother - Vincenzo Pentangeli - flown in from Italy to sit in the audience and remind his brother Frank of his oath to the brotherhood. It worked. Trump is Vincenzo Pentangeli.
UPDATE 02:55 pm: Somebody told him.

