Elon Musk purchased Twitter with the avowed purpose of restoring free speech because, he said, it is “important to the future of civilization to have a common digital town square, where a wide range of beliefs can be debated in a healthy manner without resorting to violence.” Twitter is still in a transition period under Mr. Musk’s new leadership. Nevertheless, United Nations High Commissioner for Human Rights Volker Türk decided that he could not wait before strongly urging Mr. Musk, in an open letter he wrote earlier this month, “to ensure human rights are central to the management of Twitter under your leadership.” Mr. Türk then laid out in his letter six fundamental principles from a human rights perspective that he believes Twitter must follow.