One of the biggest casualties of Donald Trump’s presidency is the reputation of H.R. McMaster, who continues to hold the rank of three-star general while serving as the national security adviser. The Daily Beast reported Thursday that a “growing cadre of former military officers” who served with McMaster want him to retire, fearing he’s “tarnishing the military’s reputation” by serving as Trump’s “political shield.” “H.R. is being used here,” a former McMaster colleague told the Beast. “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.”

McMaster joined the administration as a figure of genuine renown, a soldier-scholar who had authored a much admired book on the Vietnam War and led some of the most famous missions in the Gulf War and the Iraq War, where he was an innovator in counterinsurgency strategy and an architect of the successful troop surge in the last years of the Bush administration.

But in recent weeks, McMaster has taken on the role of the bodyguard, brandishing his reputation to defend the president’s most controversial actions. On May 15, when The Washington Post revealed that Trump had shared sensitive intelligence with the Russians, McMaster came out with a categorical denial, stating, “The story that came out tonight as reported is false.” McMaster later softened this statement until it amounted to a non-denial denial, one that challenged the “premise”of the Post report but didn’t contest the facts.

In a scathing critique of McMaster’s subservience to Trump, the venerable national security reporter Thomas Ricks argued in Politico, “I no longer believe in the ‘adults in the room’ theory of containing President Trump and the similarly erratic and ignorant people around him.... I don’t see McMaster improving Trump. Rather, what I have seen so far is Trump degrading McMaster. In fact, nothing seems to change Trump. He continues to stumble through his foreign policy—embracing autocrats, alienating allies and embarrassing Americans who understand that NATO has helped keep peace in Europe for more than 65 years.” Ricks called for McMaster to step down—“not just for his own good, but for the good of the country.”

McMaster’s services to Trump include not just protecting the president from scandal but providing an intellectual sheen for his foreign policy. In The Wall Street Journal this week, McMaster and Gary Cohn, director of the National Economic Council, published an op-ed making the case for an “America First” foreign policy:

The president embarked on his first foreign trip with a clear-eyed outlook that the world is not a “global community” but an arena where nations, nongovernmental actors, and businesses engage and compete for advantage. We bring to this forum unmatched military, political, economic, cultural, and moral strength. Rather than deny this elemental nature of international affairs, we embrace it.

As The Atlantic’s David Frum noted, the op-ed amounted to a wholesale acceptance of Trump’s foreign policy vision: that America is a lone-wolf nation that eschews international order in favor of zero-sum combat. Frum wrote that “perhaps the most terrifying thing about the Trump presidency is the way even its most worldly figures, in words composed for them by its deepest thinkers, have reimagined the United States in the image of their own chief: selfish, isolated, brutish, domineering, and driven by immediate appetites rather than ideals or even longer-term interests.”

There’s no mystery why Trump wanted to recruit a figure like McMaster, along with other military men like Defense Secretary James Mattis and Secretary of Homeland Security John F. Kelly, both retired generals. While Trump is a polarizing president, the military is one of the most trusted institutions in America. In fact, many of the virtues commonly associated with the military—discipline, self-sacrifice, an honor-based moral code—are all qualities that Trump notably lacks.

The esteem for the military led many conservatives to place their hopes for Trump’s presidency in the appointment of figures like McMaster. “Thank God for the generals,” Eric Fehrnstrom wrote in the Boston Globe in early April. “No one thought they would turn out to be the moderates in the Trump White House. In an administration riven by staff bickering and internal disputes, President Trump’s senior military appointees are taking a leading role and acting as a restraining influence.”

The swift decline in McMaster’s reputation, from a widely admired figure to Trump’s lackey apologist, shows how foolish it was to put so much faith in military appointments. The truth is that to keep Trump’s confidence, McMaster and the other generals have to meet Trump more than halfway. They have to constantly cover for his erratic behavior and justify his policy chaos. As Ricks notes, “Mature national security specialists seasoned in the ways of Washington simply lend an air of occasional competence to an otherwise shambolic White House. By appearing before the cameras, looking serious and speaking rationally, they add a veneer of normality to this administration. In the process, they tarnish their own good names.” And in the case of McMaster, as the Beast report suggests, he’s tarnishing the military, too.

These analyses rest on the assumption that the generals were unassailable before joining the administration. But if they could be so easily tarred by Trump—indeed, if they could be so easily convinced to serve an ignorant, incompetent commander-in-chief—perhaps their initial reputation wasn’t really merited. The core assumption Trump has exploited is that military officers are unbiased, apolitical patriotic professionals. But a moment’s reflection should tell us that military leaders have the same worldly ambitions as other mortals. The Beast suggested that McMaster took the national security adviser position as a way of giving new life to his military career and earning a fourth star.

The generals may also have specific policy objectives. There’s every reason to believe, for instance, that McMaster and Mattis are ultra-hawkish on Iran. If that is their overriding foreign policy objective, it’s possible that their compromise with Trump has an ulterior ideological motive. They are willing to give Trump cover on many issues— including, in McMaster’s case, possible Russian collusion—in exchange for achieving a harder line, and possibly war, against Iran.

Instead of taking the generals as sources of pure disinterested wisdom, we’d do well to see them as having as much of an agenda as anyone else in Washington. If McMaster is willing to trade his good name for a chance to whisper in Trump’s ear, he’s no different than Jared Kushner, Steve Bannon, Paul Ryan, or any of the other courtiers bending the knee before Trump. As always, Trump is a clarifying figure: in this case, disabusing us of the myth of the American military as non-ideological svengalis. McMaster, by this light, isn’t sullying his reputation or that of the military. Rather, he’s showing his true colors.