Members of a military band rehearse on the West Front of the U.S. Capitol in Washington on Jan. 19, 2017. (Photo by Joe Raedle/Getty Images)

Imagine a U.S. president whose management of international relations strikes many in the political establishment as dangerous and contrary to the U.S. national interest. Imagine further that Congress, run by the president’s party, appears unwilling to challenge the president, while the news media is profoundly distrusted by half the country. This president’s administration starts provoking countries that have powerful militaries, perhaps even nuclear weapons. Many of the military’s top brass begin to fear the president’s strategies are risking a crisis that could lead to a devastating war.

Should military leaders remain publicly silent about the president’s provocative foreign policies, as American tradition demands? Or should they speak out – and risk compromising the military’s professionalism and tradition of staying outside politics?

Let’s examine how such a challenge to U.S. civil-military relations might come about – and what the consequences might be for the United States as a nation.

The U.S. has a powerful tradition of civilian control of the military

Among the United States’ founding principles is the concept – grounded in the Constitution – that civilians  will control the military. The country maintains an apolitical and professional military, subject to the president and Congress, in part through the Uniform Code of Military Justice and Department of Defense regulations that prohibit political activity.

But the most important factor in keeping the military apolitical is cultural: the military’s own commitment to socialize its personnel to behave like professionals. The U.S. military tradition demands that active-duty personnel stay out of public debate about different foreign policies or use of force.

Senior military officers must provide unvarnished advice about the use of force when, in private, civilians ask. But once the president makes a decision, military leaders must carry it out without complaint – even if they think the decision could endanger the country or the men and women under their command. As civil-military relations scholar Peter Feaver captures it, in the American system, “civilians have the right to be wrong.”

To be sure, this norm isn’t always perfectly followed. My research analyzes the types and consequences of the political activities in which militaries engage in democracies, and especially in the United States.

But in the United States, that cultural norm is strong. When officers do stray into politics, their military counterparts quickly admonish them. Lately the chairman of the Joint Chiefs of Staff has regularly reminded officers to adhere to norms of military professionalism.

But these norms may be severely tested during the Trump administration – and could fail altogether. Here’s why.

The military is the U.S.’s most respected institution

According to Gallup polling and other studies, the military is the nation’s most socially respected institution. That’s in part because of its professional ethos of staying above the political fray.

But that respected and apolitical status gives military leaders political power to influence public opinion. Normally they do not use that power. But under extraordinary circumstances they might.

So what makes the present extraordinary? Several things. First, President Trump and his advisers seem inclined toward provocative strategies in high-stakes regional conflicts with major military powers in Europe, Asia, and the Middle East.

Next, the president is unusually inexperienced in international affairs, and has iconoclastic approaches to  foreign relations. This could make it more difficult for him to manage deftly a complex international crisis.

Further, the normal checks on presidential action are especially frayed just now. Given the United States’ highly polarized politics, the Republican-controlled Congress might not be willing to break ranks with the president – even if some members worry about his actions. Many Americans distrust the conventional news media and primarily follow the points of view within their information silos. If military sources leak their concerns to the press, a skeptical public may dismiss it as “fake news.”

Military leaders might be called to action

If the stakes are high enough — if true disaster looms — military leaders could use their political capital to push the White House to reconsider how it is managing an escalating international crisis.

The chairman of the Joint Chiefs of Staff might be pressed to publicly question a dangerous strategy. Or the service chiefs might resign in protest. Research shows that when military leaders speak up about the use of force, they can sometimes influence public opinion.

The president might also try to recruit allies in the armed forces to make statements in support of the administration’s strategy. He has already tested the norms of military professionalism that separate the military from politics in his Cabinet appointments and in his recent speech at U.S. Central Command, where he publicly referenced the military’s support for him in the election.

But there would be consequences if the military broke its professional norms

In a dangerous international crisis, military leaders concerned about the president’s strategy face two bad choices. Saying nothing leaves them forever burdened with the knowledge that they might have averted a horrific war.

On the other hand, if military leaders speak out, the president’s supporters might question their motives and accuse them of partisanship. Evidence suggests that when officers are seen as partisan, Americans’ view of the military is tainted. Still, given the stakes involved, military leaders might feel they must this one time violate their professionalism and publicly criticize the president’s strategy.

But that could do long-term damage to the country’s civil-military relations. By stepping in to avert war, military leaders are telling Americans that their civilian leaders do not, in fact, have the right to be wrong – that military leaders know best about strategic matters and should influence such decisions. With each new controversy in the country’s foreign affairs, military leaders would be pressured to speak up. Factions in the officer corps might start to take sides in public debates about national security.

That would be costly not just to the military, but to the country. The military would lose its professionalism and possibly its social esteem. The country would lose its apolitical officer corps and its bedrock tradition of civilian control of the military.

Risa Brooks is Allis Chalmers Associate Professor of Political Science at Marquette University. She is the author of Shaping Strategy: The Civil-Military Politics of Strategic Assessment (Princeton University Press, 2008).