A new book reports that Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, improperly restricted the president of the United States’ ability to use military force and committed to warning China, an American adversary, of any impending U.S. military action against it. If the book, “Peril,” by Bob Woodward and Robert Costa, accurately recounts General Milley’s behavior, his actions could be an egregious series of violations of the norms that govern civil-military relations in the United States. The context surrounding General Milley’s actions is unclear and may…