On Tuesday night, Donald Trump committed a huge no-no. This was nothing trivial like empowering white hate groups or waging public and legal vendettas against his enemies—he’s been doing those things all along. For the first time since winning the presidency last week, he sneaked away from the pool of reporters tasked with knowing his whereabouts all day every day to dine at a fancy Manhattan steak house.

This may sound like a minor infraction, but it is actually a matter of incredible importance, as many journalists have explained in the hours since.

Trump had traduced yet another vital norm, except instead of simply noting an objection to the violation, and assuming the importance of the broken protocol, reporters have been at pains to defend it. Pool duty isn’t the most glamorous assignment, but it is some of the most vital work political reporters do, because when someone is vested the power of the presidency, history is always at his fingertips. The public has a right to know what the president of the United States is doing, but so does history. As Yahoo! News chief Washington correspondent Olivier Knox explained Wednesday, “it’s designed to tell Americans, and the world, about the president’s whereabouts and well-being in the event of a crisis, and how the president is responding. At its grimmest, it’s sometimes called a ‘body watch,’ the bleak legacy of the assassination of JFK and the attempted murder of Ronald Reagan.”

The protective pool doesn’t dine with the president, but posts nearby, usually out of sight, in case anything from a terrorist attack to an untimely heart attack happens when the president and his staff are away from official outposts where the full press corps can assemble. Pool reporters don’t do this for access—usually little access is provided. They do it so that documenting the presidency doesn’t fall exclusively to interested parties who work for the president’s administration. They do it so that news reporters don’t have to tell the world that nobody knows where the president is.

The defense of the protective pool norm has been deployed passionately, and righteously, but on that score it is the exception that proves the rule. Trump shatters norms on a nearly daily basis, but typically his recklessness is noted, objected to, and then largely forgotten. Reestablishing these broken norms will require the establishment of a new one: a free press that internalizes its role as a defender of values beyond the free press itself.