In the two days since President Trump’s tweets barring transgender troops from the U.S. armed forces, a consensus has emerged among senior military leaders and members of Congress that those tweets do not constitute an official policy announcement. “We don’t have guidance. We have a tweet. We don’t execute policy based on a tweet,” said one Pentagon spokesperson.

This creative interpretation allows Pentagon leaders to avoid conflict with their commander in chief, and maybe signal a little dissent too. It’s a posture, though, that has little basis in law. Military officers and Cabinet officials have a legal duty to obey presidential orders and statements of policy, no matter what form they take. This kind of clever disobedience only adds uncertainty to the chain of command and could create bigger problems in the event of a real crisis.

The Constitution vests the “executive power” of the nation in the president with little discussion as to what that actually means. Nothing in the Constitution describes precisely how the president should exercise that power, let alone communicate statements of policy or directives to subordinates. In 1935, Congress passed (and President Franklin Roosevelt signed) the Federal Register Act, which specified the format and publication requirements for executive orders, the most formal kind of presidential edicts. A decade later, Congress passed the Administrative Procedure Act, creating a laborious and highly legalistic process for establishing or eliminating government regulations. While these statutes and rules govern what gets published as a formal executive order, they do not cancel out the president’s ability to set policy by other means. Doing so would impermissibly tread on the president’s prerogative as chief executive.

Modern presidents have relied on a variety of tools to announce policies or direct their subordinates. In addition to formal executive orders, the presidential arsenal includes speeches, memoranda and directives, budget submissions, and notes from important meetings like those of the National Security Council. That Trump would add tweets to this list makes sense and simply reflects the evolution of political communication. If it was fair and appropriate for President Obama to announce policy in a speech, then it is also fine for Trump to announce policy in a morning tweetstorm.

The common denominator here is that presidential words matter. Every presidential statement, no matter the form, is a statement of American policy. That’s true whether the statement is an eloquent speech given at the Berlin Wall, an executive order run through the bureaucratic grinder, or a spontaneous tweet from the current president. The White House is correct to say as much, as are the courts that are now weighing the probative value and legal force of presidential tweets.

Obviously (and thankfully), our nation came of age before the advent of social media. But even in the age of horse-borne messengers and handwritten letters, presidents used casual communications to establish and direct policy. President George Washington’s archives are replete with examples of letters—some formal, some much less so—conveying his wishes to Cabinet officers and political colleagues. During the Civil War, President Abraham Lincoln famously exchanged letters and telegraph messages with his generals, some dripping with sarcasm or anger. For their part, Lincoln’s generals frequently dissented or disobeyed the president’s missives by requesting clarification or feigning ignorance, or simply blaming the unreliability of 19th-century telecommunications.

Nearly a century later, President Harry Truman wrestled with a similar problem during his dealings with Gen. Douglas MacArthur, the commander of U.S. forces fighting the Korean War. Truman and MacArthur never saw eye to eye on how best to prosecute that war, nor how to avoid escalation of the war or provocation of China and the Soviet Union. Truman used a variety of messages, letters, and emissaries to telegraph his intent to MacArthur, but all were studiously ignored by the American Caesar. Eventually, Truman fired MacArthur when the disobedience reached a boiling point, but not before MacArthur erred and brought China into the war, arguably costing thousands of American lives.

The civil-military relationship has changed substantially since the days of Truman and MacArthur. With some input from Congress, today’s military now runs under a highly organized, bureaucratized system of orders, with elaborate coordination and approval requirements for even the smallest deployments of troops. Within this system, the secretary of defense must personally approve and hand-sign orders for units deploying overseas. Operational missions, such as special operations raids or bombing runs, must also be approved at similarly high levels, sometimes by the president himself where there are significant risks or foreign policy concerns.

And yet, for all this bureaucracy, a tweet or speech still counts as presidential policy. Senior leaders can no more ignore these directives than they can a well-crafted memorandum that comes from the NSC staff. By dissembling about Trump’s tweets and insisting they are not policy, senior government leaders are playing a dangerous game, effectively substituting their authority for that of our elected president.

While feigning misunderstanding may avoid conflict for now, it creates uncertainty that could explode into chaos in the future. Imagine that North Korea has just launched a missile (as they apparently did on Friday.) As is his wont, President Trump tweets his reaction immediately and also announces his intent to put U.S. forces on alert. “Oh, that’s not an order, that’s just a tweet,” the generals might respond, cautioning their forces to remain at normal posture lest they provoke a larger war. And then the second North Korean attack comes, this time targeting U.S. troops in South Korea, who had been told by their generals to ignore the presidential tweet. The uncertainty created by Trump’s vague and uncoordinated tweets, and the hesitant responses among military leaders to those tweets, could cost lives. An extreme example, to be sure, but one that feels more plausible after this week.

It’s clear that military leaders still don’t quite know what to make of Trump—a man who studiously avoided military service and all things relating to it for his whole life only to find himself in charge of the national security establishment. His bombastic style may appeal to voters, and even some troops, but it is a study in contrast with the generals who lead today’s military. And yet, that difference in style, or even significant disagreements with the president on policy, does not entitle senior military leaders to disobey the president. Consider how it would look if a Democratic president ordered the immediate integration of transgender troops, only to find his or her order fumbled by disagreeable brass. We might label that a soft coup and criticize the generals for acting as an undemocratic deep state.

Today’s military craves a civil-military relationship in which it will receive clear orders from the president to perform discrete tasks with well-defined outcomes. And yet, the real world is messier than that, and so is our current president. Our military will need to learn to accept a president who does not communicate in traditional ways, nor respect established norms of civil-military relations. Delaying implementation of a vague policy announced by tweet is not the same as disobedience, but it’s a step in that direction.