The final weeks of the 2016 presidential campaign are once again highlighting the controversial role retired generals and admirals now play in national politics. Earlier this month, candidate Trump released a letter signed by 88 retired senior officers who support his presidential run. Candidate Clinton followed suit the next day, releasing her own list of 95 retired generals and admirals who have officially endorsed her for the highest office in the land. Retired generals and admirals have continued to publicly trade partisan blows.

Many Americans no doubt see these military endorsements as just another effort to line up various interest groups to support the presidential candidates — not that different from getting an endorsement from the American Legion or labor unions. But that view is profoundly and dangerously wrong. Retired generals and admirals publicly endorsing candidates for president is not just more politics as usual. It deeply affects the profession of arms by putting at risk the apolitical reputation of the U.S. military and by eroding civilian leaders’ trust in the non-political nature of our senior uniformed military leadership.

Retired senior military officers — those who will always bear the title “General” or “Admiral” before their names — have a special responsibility as highly visible symbols of the most respected institution in America, the U.S. military. These most senior of officers have a lifelong duty to protect the apolitical character of the institution they long served, even when they no longer are on active duty. And their schooling in that special responsibility must start from the day they pin on their first star — something that does not occur today.

All Americans expect that their uniformed senior military leaders adhere to the proper norms of civil-military relations — particularly the immutable expectation of civilian control of the military. Serving senior officers also fully understand the importance of avoiding any perceptions of political bias or affiliation by any members of the force while in uniform. In August, Chairman of the Joint Chiefs of Staff Gen. Joe Dunford explicitly reminded serving military members to remain apolitical, since the new president needs to have trust and confidence that the military “is completely loyal and completely prepared to do what must be done.”

Yet the political role of retired generals and admirals seems to increase with every presidential campaign, and it has reached new heights in this year’s highly contentious race. Retired Lt. Gen. Mike Flynn spoke at the Republican National Convention under a photo montage that included his picture in Army dress uniform, and he repeated the phrase “lock her up” after it was enthusiastically chanted by the audience. At the Democratic National Convention, retired Marine Corps Gen. John Allen marched onstage to martial music, introduced himself as a “retired four-star general of the United States Marine Corps,” and then castigated the Republican candidate to his cheering audience.

These primetime endorsements are much sought after by candidates, with the goal of establishing the national security credentials of the nominees by implicitly connecting them to highly visible representatives of the U.S. military. As former Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey recently noted, Flynn and Allen weren’t onstage as Mike or John — for all intents and purposes, their first name was “General.”

Flynn, Allen, and every other retired senior military leader all possess the same rights to free speech as any other citizen. But just because they can endorse political candidates does not mean that they should. Doing so instantly turns retired generals and admirals into partisan political figures and poses grave civil-military dangers. Future presidents may question whether their uniformed senior military leaders can be trusted to be apolitical advisors sharing best military advice untainted by political leanings. And the appearance of generals just weeks or months out of uniform among the ranks of the political opponents of an administration still in office makes that concern sharper still.

If U.S. elected leaders are to maintain trust in an apolitical military whose uniformed leaders aren’t seen as simply waiting in the wings for their opening to a future political role, the current norms that tolerate endorsing political candidates must change. After the conventions, Dempsey took the unusual step of urging his fellow retired generals and admirals to keep their political opinions to themselves, and encouraged politicians to keep retired military leaders off the stage because “the military is not a political prize.”

Yet it is too late to try to instill proper norms of civil-military conduct once these senior officers have already retired. Expectations must be set early, while generals and admirals are still serving on active duty, to create a lasting change in behavior. Norms proscribing political endorsements should be established from the moment an officer pins on his or her first star and must be continually reinforced throughout the rest of his or her career and into retirement. Current service chiefs and four-star leaders must bring about this change, since they are the moral compass of the profession of arms — and they must also serve as exemplars of these norms after leaving active service.

How could this be done? One important way to start would be for every newly selected general or admiral to receive a letter from the chairman of the joint chiefs of staff, co-signed by his or her service chief, that went something like this:

Dear General (or Admiral):

As you prepare to pin on your first star, you are about to join the ranks of a truly select few in the U.S. military — America’s flag and general officers. You will now be responsible for leading this great force of young Americans at our most senior uniformed ranks — a sobering responsibility. You will also be forever viewed as a representative of our profession once you pin on these stars. I want to share with you some of the expectations of the profession of arms that come with your new rank.

You will continue abide by your oath to support and defend the Constitution of the United States against all enemies, foreign and domestic. But as a general, your responsibilities to the republic will from this day forward will be much greater than those you have held to date. And they will extend beyond your years on active duty, since you will hold the title of general for the rest of your life. That title brings with it a lasting commitment to protect your nation and uphold the reputation of the U.S. military. You should understand the lifelong nature of this duty as an inherent part of accepting this promotion.

You will be expected to always uphold the honor and standards of our profession, no matter what path you choose after your military career. One of the most important of those standards is protecting the nation’s proper civil-military relationship once you leave active duty.

The U.S. military must remain — and remain to be seen as — an institution above politics, apolitical in every way. There are no Republican generals or Democratic generals, only American generals. Our system rightfully places elected and appointed political leaders in charge of the U.S. military, a principle of civilian control of the military that you have fully embraced since your first oath of office. Your commitment to that principle extends beyond your time in uniform and into retirement, as well.

Our profession expects you to refrain from direct participation in national politics employing the credentials of your rank and service. You are free to offer advice, counsel, and testimony drawing on your years in uniform or to run for elected office yourself. You should continue to be a resource of knowledge and experience for our nation. But you should not permit your name and the prestige of your senior rank in the military to be used for political purposes. You should not allow your title and service to be associated with endorsements for any particular national candidate — most especially for the presidency. To do so taints the apolitical reputation of the serving senior ranks of generals and admirals, and it risks undermining the confidence of our elected leadership in the apolitical nature of our armed forces. Put simply, our elected and appointed civilian leaders must have every confidence that the military advice from uniformed leaders they are receiving is free of political bias. To ensure this, retired senior officers cannot become partisan political advocates upon leaving uniform.

Selection for promotion to general or admiral is a great honor and entails a lifelong commitment for those who accept its obligations. This letter serves to remind you of their enduring nature as you first take on those responsibilities. My successors and I will continue to share these expectations with you on each of your subsequent promotions and appointments, and once more as you prepare to leave active duty.

Our fellow citizens join with me in offering you warmest congratulations on your selection, and we commend your willingness to take on the lifetime commitment to our profession and the nation that those stars represent.

Warm regards,

The Chairman of the Joint Chiefs of Staff and Your Service Chief

Lt. Gen. David W. Barno, USA (Ret.) is a Distinguished Practitioner in Residence, and Dr. Nora Bensahel is a Distinguished Scholar in Residence, at the School of International Service at American University. Both also serve as Nonresident Senior Fellows at the Atlantic Council. Their column appears in War on the Rocks every third Tuesday. To sign up for Barno and Bensahel’s Strategic Outpost newsletter, where you can track their articles as well as their public events, click here.

Image: U.S. Marine Corps photo by Michael Thorn