WASHINGTON — Pete Hegseth’s tenure as Secretary of Defense has been marked by unprecedented internal upheaval within the Pentagon, as his approach has brought cultural battles into the heart of the U.S. military at a time of ongoing strategic challenges.

Unlike previous defense chiefs who generally sought to shield the armed forces from political and social discord, Hegseth has intensified efforts to reshape the military’s culture, sparking widespread controversy. His administration has overseen the removal or blockage of promotions for as many as 80 generals and admirals, with senior leaders and career officers describing the scale and pace of these personnel changes as unparalleled in modern Pentagon history. Many express concern that trusted, combat-tested officers have been sidelined without clear explanations, raising questions about the impact on military readiness and morale.

The upheaval has coincided with extended military commitments involving Iran, where stretched deployments and shortages in critical missile defense systems have tested U.S. force capabilities. Some military officials interviewed on condition of anonymity said Hegseth’s internal focus has distracted senior leadership from addressing these pressing operational challenges, contributing to a growing climate of mistrust within the ranks.

General Dan Caine, chairman of the Joint Chiefs of Staff and the top military adviser to Hegseth and President Donald Trump, has faced scrutiny as well. Officers across all ranks have expressed doubts about whether Caine has effectively protected the force from the cultural conflicts driven by Hegseth. The chairman has been reticent to discuss his advisory role publicly. A spokesman for Caine declined to comment on the general’s counsel.

Hegseth, a former Army National Guard officer who served in Iraq and Afghanistan and left the military in 2021 following controversy over tattoos labeled extremist by the Army, has championed a return to what he calls a “warrior ethos.” In public addresses, he has called for an apolitical, tough-minded military, criticizing what he views as a left-leaning agenda undermining discipline and cohesion.

Pentagon spokesperson Kingsley Wilson described Hegseth’s goal as restoring combat effectiveness eroded by bureaucratic hurdles and institutional inertia. However, many military leaders argue that his approach has instead weakened the institution by targeting experienced officers and fostering uncertainty. Key leadership positions have remained vacant for extended periods, prompting some career officers to question whether to continue advancing within the military hierarchy.

Hegseth has also imposed new restrictions on educational opportunities for midcareer officers, blocking attendance at highly regarded graduate programs at institutions such as Harvard, Princeton, Columbia, and Yale. These moves reflect his skepticism toward what he deems politically charged or ideologically biased academic curricula. The review extends to officers’ academic work, including master’s theses, with at least two promotion candidates reportedly denied advancement based on objections to their research, which addressed subjects like race and political polarization within the military.

Critics contend that this scrutiny has suppressed open inquiry and intellectual rigor, qualities long valued by the services. Peter Feaver, director of Duke University’s American Grand Strategy program, questioned whether the Pentagon under Hegseth prioritizes critical thinking or demands adherence to predetermined viewpoints. Former Chairman of the Joint Chiefs Gen. Charles Q. Brown, whom Hegseth dismissed last year, expressed concern that some officers are being punished for fulfilling their professional duties or are being exploited in the culture wars.

Supporters of Hegseth within the military have defended his actions. Army Col. Kevin T. Black recently praised the secretary’s efforts to confront what he described as a protected class of officers whose promotions were allegedly disconnected from mission readiness.

General Caine’s leadership style has reflected a cautious approach amid these internal tensions. Addressing National Defense University graduates, Caine emphasized his role as an adviser focused on the military’s ability to execute missions rather than engaging in policy debates. He encouraged continued learning and intellectual curiosity despite restrictions imposed on officer education, citing the example of Brent Scowcroft, former national security adviser, who earned advanced degrees during his military career at institutions now largely off-limits to officers under the current administration.

As the Pentagon grapples with both external threats and internal discord, the question remains whether the current leadership’s approach will strengthen or erode the U.S. military’s long-term effectiveness.