A growing cadre of former military officers who served with Trump National Security Adviser H.R. McMaster are quietly calling for him to retire from service, worried the embattled Trump administration is tarnishing the U.S. military’s reputation by deploying their own personal three-star general as a political shield.

In recent weeks, McMaster has acted almost as a White House spokesperson, thrust into the spotlight to promise that President Donald Trump didn’t reveal anything inappropriate when he shared another spy agency’s intelligence with two Russian officials in the Oval Office. McMaster was also the face—or the voice—of the administration on Trump’s first foreign trip, giving off-camera interviews to explain what the president hoped to accomplish from Saudi Arabia to NATO.

Trump himself gave no interviews, as news broke back in the states that his son-in-law and key organizer of the trip, Jared Kushner, had reportedly sought to establish back-channel communications with Russia, using Russian communications equipment. McMaster claimed he was “not concerned” by “back-channel communications,” though fellow military professionals say what Kushner proposed went far beyond discreet diplomacy.

“It makes me uncomfortable that a serving military officer is in that role,” said a retired senior military officer who calls McMaster a friend. “The credibility he has is precisely why they are using him as a spokesman. I think that’s unfortunate.”

“H.R. is being used here,” added a former military adviser who worked with McMaster overseas. “If he didn’t have three stars on his shoulder, he’d be useless to them. It’s the worst of all outcomes for him. He’s got this miserable interagency process and then gets trotted out to defend the most inane and corrupting things,” said the adviser who spoke anonymously, like others in this story, fearing reprisals from the Trump administration.

Current and former army military officers have expressed to The Daily Beast unease with how the Trump White House has sent McMaster repeatedly into the political breach to defend the commander in chief’s actions to the American public.

That’s fueling calls for the maverick Army officer to retire from military service if he wants to stay in the White House, lest his increasingly political role damage the U.S. military’s reputation as being above party and politics.

“He has to retire,” said an officer who served with McMaster overseas. “Being the national security adviser that this president requires—given the random things Trump’s going to say that he has to defend—he can’t do that in uniform.”

McMaster’s most recent foray into “defense of Trump” territory came in the form of a Wall Street Journal op-ed that praised Trump and slammed Obama administration policies.

The Wall Street Journal article was rolled out after Trump’s first foreign foray, as German Chancellor Angela Merkel was warning darkly that “The times in which we could rely fully on others, they are somewhat over.” She reflected near-universal grumbling by NATO leaders after Trump lectured them that they were failing to invest enough in their defense, leaving the U.S. to make up for the shortfall.

“America will not lead from behind,” countered McMaster and co-author Gary Cohn, director of Trump’s National Economic Council. It was a not-so-subtle reference to a criticism often aimed at the Obama administration. “This administration will restore confidence in American leadership as we serve the American people,” they add.

To some former army officers, McMaster’s op-ed smacked of lauding the current administration at the expense of the last one.

“In the first paragraph, he takes a swipe at Obama, then he goes well within the language of political adulation,” said former Army officer Dr. Jason Dempsey. “For H.R. to write an overtly political piece, to be a front man for the administration, and to sign as Lt. Gen. H.R. McMaster, the norm of officers keeping their mouths shut on partisan political matters is just dead,” said Dempsey, who researches civil-military relations at the Washington, D.C.-based Center for a New American Security.

Serving soldiers are not allowed to take part in overt political campaigns, according to Army Regulation 600-20. That includes “any outward or demonstrable activities or support for partisan political parties, candidates, or issues,” one army manual warned soldiers ahead of last year’s election.

But legal experts say McMaster would only have to append a personal disclaimer that his writing does not reflect the government’s view, if he was criticizing Trump’s policies.

“I don’t see a violation because he’s focusing on an issue rather than a candidate or a party,” said Richard Painter, former chief White House ethics lawyer for George W. Bush, in an interview. “He’s not seeking to influence an election,” said Painter, who now teaches at University of Minnesota Law School.

“He’s not explicitly endorsing a presidential candidate. He’s clearly engaging in strategic messaging in support of Trump’s objectives,” agreed Jason Wright, a national security lawyer and former Army lawyer, in an interview.

“From our standpoint, we concur with the legal opinions and would point out the Powell precedent,” a senior administration official said, citing a 1989 New York Times opinion piece penned by then-active-duty Lt. Gen. Colin Powell.

Of those who say he should retire, “They are entitled to their opinion, but he is doing the job to the best of his ability,” the official said, speaking anonymously because the official was not authorized to comment on the matter publicly.

McMaster did intend to retire from his last job in the army, before being asked to stay on to serve President Trump, according to two former military officers familiar with his thinking. The national security adviser job was an unexpected “Hail Mary pass” for his army career, giving him a chance of earning a fourth star, they said, speaking anonymously to describe their discussions with him.

McMaster is the third active-duty national security adviser, after Vice Admiral John Poindexter and Lt. Gen. Colin Powell, who were both appointed by President Ronald Reagan. Alexander Haig and Brent Scowcroft served as the deputy national security advisers while still in uniform, and under President George W. Bush, Lt. Gen. Douglas Lute served as deputy national security adviser for Iraq and Afghanistan before retiring and staying in the post as a civilian.

The way each national security adviser is perceived depends on how their particular commander in chief uses them: as a coordinator of national security agencies; or as a shield of military propriety.

Dempsey, reflecting the views of many who spoke anonymously, said what he sees as McMaster’s partisanship adds to the danger that the American public may start seeing the military as political, because there are so many former military officers in the Trump administration.

In a Center for New American Security report, Dempsey and his co-author Amy Schafer write that it reflects a trend of more politicization of the military’s ranks, demonstrated by the prominent speeches retired generals made at both Republican and Democratic national conventions in 2016.

A recent National Defense University study also found more troops are expressing their views on political candidates or leaders through social media despite the military’s ban on overt displays of political support (PDF). “A striking percentage of the 500+ individuals surveyed reported that their military friends, both active duty and retired, have used or shared insulting, rude, or disdainful comments directed against political leaders on social media,” wrote study author Col. Heidi Urben.

“Better H.R. than Mike Flynn,” Trump’s first national security adviser, the former military adviser said. “At least when Flynn was there, you knew it was a disaster. H.R. gives them the patina of respectability,” the former military adviser said.

This adviser, like so many in the military community, revered McMaster for his battlefield prowess, his scholarship, and his willingness to speak truth to power. And that made his current role as a voice for this most controversial of administrations all the more jarring.

“H.R., by virtue of his scholarship and service, is the standard for military professionalism and integrity for a whole generation of military officers. And that’s a heavy burden to carry,” said former Army officer Paul Yingling.

Yingling added that he was unwilling to either critique McMaster or disclose any conversations he may have had with his former commander. But, echoing a plea he published on the Foreign Policy website, he insisted that active duty officers must maintain a strict code of conduct that civilians do not.

“An officer cannot tolerate a lie. It’s not enough to tell the truth,” Yingling told The Daily Beast. “You have to be not just truthful but completely honest. You can’t remain silent while others lie. That is the dilemma of any officer serving in the strategic and political world…You have an obligation to tell the full truth, including correcting the record when others misrepresent it.”

Without openly faulting McMaster, Yingling hinted that obligation is at odds with McMaster’s new duties as a face of the Trump administration. Team Trump “obviously has not been forthcoming about its contacts with Russia, either as a campaign, a transition team, or an administration,” Yingling said.

McMaster was also put in an awkward position of defending Kushner’s reported attempts to communicate with Russia during the transition.

“It’s not appropriate for a transition team to seek a communications channel with a hostile foreign government, using the communications facilities of that hostile government,” Yingling said. “It’s an irrational, irresponsible risk.”

Two senior retired military officers said they understand both why McMaster said yes to the job, and why he’s reluctant to leave the army career he loves.

“It is in H.R.’s nature, as with any others, if the commander in chief calls and says I want you to do something, every bone in your body says that’s what I do, no matter how uncomfortable that may be,” one of the officers said. The second officer said if candidate Hillary Clinton had won and asked him to take the job, he likely would have said yes.

“It’s really a personal choice. If he thinks he can give the president national strategic advice that he’s required to give without tainting his military position, then more power to him,” said retired four-star Gen. George Casey in an interview. Casey commanded McMaster in Iraq, and now teaches a class on civil military relations at the Korbel School at the University of Denver.

“In my opinion, his integrity is beyond reproach as well as his work ethic and desire to do what is right,” added retired Col. Steven Boylan, who worked with McMaster in Iraq. “I feel confident that H.R. is able to provide frank advice to the President in their discussions.

“We may not always agree with their decision which leaves us a decision. We either execute the decision the best we can or if we cannot in good conscience abide by the decision, we can resign/retire depending upon the situation,” Boylan said in an email.

That’s a dilemma all the generals current and former must wrestle with, including McMaster, according to former chairman of the Joint Chiefs of Staff, retired Adm. Michael Mullen.

“Inside the White House, it’s politics all the time,” Mullen said in comments at the Center for Strategic and International Studies in Washington. “In these jobs, you get pushed to the edge of who you are.”

The retired four-star admiral said you have to decide, “What are my limits here? When am I going to say no, meaning I’m not here anymore?”

For McMaster, that time hasn’t yet come.