A series of firings and feuds initiated by Defense Secretary Pete Hegseth has left the Army essentially rudderless as it struggles to deal with the threat posed by cheap, deadly drones and missiles that have pounded U.S. bases in the Middle East. The Army has not had a chief of staff, the service’s top officer, since Mr. Hegseth fired Gen. Randy George without explanation in April, and there are no signs that he is close to filling the position, said current and former officials speaking on the condition of anonymity to discuss sensitive personnel matters.

Mr. Hegseth has forced out at least three senior officers who had been viewed as potential successors to General George. Army Secretary Daniel P. Driscoll, the service’s top civilian leader, is also expected to leave the administration in the next few months and has already moved out of the large family house that he was renting in Fort Myer, outside Washington, officials said. The turmoil comes as the Army, the military’s largest service, faces its busiest period since the Iraq and Afghanistan wars.

Beyond General George, Mr. Hegseth has fired or forced out a half-dozen senior officers — a generation of the Army’s most combat-hardened leaders — thinning the service’s top ranks for the next several years, officials said. “Hollowing out the most battle-tested and most lethal, proven leaders in a time of war means troops are less safe and we’re less likely to win,” said Representative Pat Ryan, Democrat of New York and a former Army intelligence officer.

As recently as January 2025, when Mr. Hegseth took office, there were 10 four-star generals on active duty. The service currently has five, the fewest in decades. A long-term worry is that the firings send a message that officers who provide frank military advice or fail ideological litmus tests have no place in a force that is supposed to be nonpartisan, military and congressional officials said.