With the dramatic firing of two members of the U.S. Joint Chiefs of Staff — the chairman, Air Force General C.Q. Brown, and the Chief of Naval Operations, Admiral Lisa Franchetti — President Donald Trump’s administration has shocked the armed forces. Secretary of Defense Pete Hegseth also dismissed the Air Force’s vice chief of staff, General James Slife, and three judge advocate generals (JAGS) — the top uniformed lawyers for the Army, Navy and Air Force. Trump indicated more firings of top military officials are in the offing.

How should we think about this rare purge at the very top of the uniformed military? Is it unprecedented? What are the likely consequences on the Department of Defense’s mission?

Let’s start with the legalities and precedents. Presidents, as commanders in chief, have unquestioned authority to relieve any senior military officer for essentially any reason. This power has been exercised across both political parties going back to the Civil War, when President Abraham Lincoln fired a whole series of ineffectual and indecisive generals before finding the leader he needed, Ulysses S. Grant.

Likewise, after the Japanese surprise attack at Pearl Harbor in 1941, President Franklin D. Roosevelt fired the Army general and the Navy admiral who had been in charge in Hawaii, and brought in Admiral Chester Nimitz and General Douglas MacArthur. A few years later, President Harry Truman fired MacArthur, then the nation’s top general, for insubordination and policy differences during the Korean War.

More recently, President Barack Obama fired Army General Stanley McChrystal for disrespectful conversations by his staff concerning then-Vice President Joe Biden (McChrystal was later exonerated by the Army inspector general, but by then he was out of uniform).

So, the question is not whether the president has the authority to relieve senior military officers, but whether Trump’s actions were warranted and what the repercussions on American security will be.

I know the case surrounding McChrystal all too well. He is an extraordinary leader, a former head of the fearsome Joint Special Operations Command, and an expert in special forces and counterinsurgency. I was thrilled when he became the leader of the International Security Assistance Force in Afghanistan, under my strategic command as the North Atlantic Treaty Organization’s military chief. He had an immediate and dynamic impact on the battlefield, and was a loyal subordinate and a fine shipmate.

I was deeply shocked and saddened when Obama, responding to an article in Rolling Stone magazine, fired Stan for a handful of disrespectful comments made by his aides while they were on liberty in Paris. I fought to keep him in command to no avail. Losing him altered the course of the war in Afghanistan and not for the better — had he stayed for several more years, we might have achieved a far better outcome there.

Similarly, I feel it was a major mistake to fire Brown, Franchetti, Slife and the judge advocate generals. No real reason has been given, beyond criticisms of a “woke culture” and that Hegseth is a longtime critic of the military lawyers, calling them “jagoffs” and writing that they put their “own priorities in front of the war fighters.”

I know Lisa Franchetti well, and she is anything but a so-called DEI hire. She has commanded a guided missile destroyer, a squadron of warships and two carrier strike groups in combat. She was also commander of the venerable Sixth Fleet in the Mediterranean. She is an experienced warrior and a fine strategist — her departure under these circumstances is a serious loss to the Navy.

Looking at the mass firings overall, I am struck by how this will hurt U.S. security in three serious ways.

First, at the tactical level, it will create real disruption throughout the military. Each of these officers will be replaced by other uniformed military, who themselves will be pulled from key assignments, leaving temporary voids at uncounted numbers of senior positions. (The exception is the return from retirement of Lieutenant General Dan “Razin” Caine to replace Brown as Joint Chiefs chairman). All of their staffs will likely be replaced as well, and the knock-on effect of vacant posts will be significant, especially if even more officers are summarily fired. All of the policies and the strategy direction of Brown and Franchetti need to be reexamined and reissued. Moscow and Beijing are no doubt applauding.

More worrisome is the divisive effect these firings will have over time. Senior and mid-grade officers will be looking over their shoulders at their bosses and even their peers. They will be worried about whether they will come under fire for an anodyne email they may have sent years ago expressing concern about racial tensions in America or another controversial topic. Or if they are women or people of color, they will feel they will be judged as unqualified “DEI hires” by the new administration. This will inject politics into the military, and the effects will be felt top to bottom over time.

And finally, it will be a discouraging time in the senior levels of the military. When the president and secretary of defense select a retired three-star officer to be chairman of the Joint Chiefs, they are, in effect, passing over about 40 active-duty four-star officers and 150 three-stars.

I know Caine, and he is smart and charismatic, a former fighter pilot and White House fellow. In 2009, he switched to the National Guard and became an entrepreneur, but returned to full-time service and ascended to three-star rank and a top position at the Central Intelligence Agency — a remarkable achievement. (Caine and I have both advised the VC firm Shield Capital.)

But he has a very difficult leadership challenge ahead given the circumstances around his selection and the very human reactions we can expect from the generals and admirals he has vaulted over.