Donald Trump has reportedly picked retired four-star Marine Gen. John Kelly to lead the Department of Homeland Security. Kelly’s selection, reported by The New York Times and CBS News, makes him the third high-ranking military officer in the Trump administration to fill a post normally held by a civilian.

If confirmed, Kelly will become the first member of the military to lead the department, created in the aftermath of the 9/11 attacks. The department has jurisdiction over a wide swath of the federal bureaucracy, including anti-terrorism, immigration and customs, and cybersecurity. Kelly retired earlier this year after a 40-year career in the Marine Corps. In 2010, his son died in combat in Afghanistan after stepping on a landmine.

The public shares the president-elect’s apparent preference for military officials. While confidence in institutions like Congress, the media, and big business is at some of the lowest points in decades, the military remains the most trusted institution in America. Over 70 percent of Americans express a “great deal” or “quite a lot” of confidence in the military, according to a recent poll by Gallup.

That confidence may overshadow concerns about stacking the Trump administration with too many military officers. “If you have too many generals in the kitchen, the dish is likely to be baked with even more military instruments inside,” John A. Nagl, a retired Army lieutenant colonel, told The New York Times in November. “I’m not sure that’s the recipe the United States needs for every foreign policy meal.”

Trump also selected military officers for secretary of defense and for national security adviser. The current National Security Act requires any secretary of defense to be retired from the military for seven years, in an effort to ensure civilians would retain control over the sprawling military branch.

But Trump’s choice, retired four-star Marine Corps Gen. James Mattis, retired in 2013, and an act of Congress is required to grant a waiver to the law. Congress has only granted such an exemption one other time: in 1950, when President Harry Truman nominated Gen. George Marshall to be defense secretary.

The role of national security adviser — for which Trump’s choice is retired Army Lt. Gen. Michael Flynn — has been filled more often by people with military experience, but with varying results.

Most recently, President Obama’s first national security adviser was retired Marine Corps Gen. James Jones. According to Bob Woodward’s book Obama’s Wars, Jones clashed regularly with Obama’s political aides and National Security Council appointees whom he privately called “water bugs,” “Politburo,” and the “Mafia.” He felt they didn’t have any understanding of war or foreign relations, according to Woodward. As a result of these tensions, Chief of Staff Rahm Emanuel would often sidestep Jones and talk to Jones’ deputy Tom Donilon instead. Jones eventually stepped down in October of 2010, and Donilon took his place.