It’s time to think hard about Nixon v. Fitzgerald.
Fitzgerald isn’t really part of the national security law canon; it’s a 1982 Supreme Court decision that is often cited for the proposition that the President has “absolute immunity” (meaning he cannot be sued in his personal capacity) for any acts he undertakes while he is President.
We’re about to experience a flood of litigation testing what the case really means.
For most of American history, a sitting President’s immunity from civil litigation has been a subject of academic curiosity, but little real-world interest. Presidents get sued daily, of course, but usually in their capacity as head of the federal government, where—for the most part—Congress has waived any immunity. They generally don’t get sued in a manner that seeks to hold them personally liable.