The court could reject absolute immunity but grant Mr. Trump a more limited form of protection like the qualified immunity that can apply to other government officials. If it does that, it could also well leave it to lower courts to sort out the contours of what that means.

The Supreme Court’s conservatives often accuse liberals of inventing provisions nowhere to be found in the Constitution. Now, the fingers are pointed in the other direction. At the attention-grabbing arguments this week over Donald Trump’s claim of sweeping presidential immunity from criminal prosecution,