Two years into his presidency, Donald Trump is fueling unprecedented uncertainty and anxiety inside the Pentagon. In private conversations over the past month, many of them unsolicited, more than a dozen key military officers, enlisted personnel and senior civilians have expressed worry and concern to CNN. None of the officials have spoken publicly about this, as military law prohibits active-duty personnel from criticizing a sitting president.

It’s not just Trump’s unpredictable decision making that has officials on edge, it’s also his penchant for politicizing the military— something that’s come into focus in recent months as he’s struggled to fulfill his campaign promise to crack down on immigration and build a border wall. His decision to draw down troops in Syria and his claims that ISIS is defeated have also rankled military commanders who felt it wasn’t well thought out.

Some of the highest-ranking officers say there is a new atmosphere of unease inside the Pentagon, particularly among some of the most senior ranks, over the President’s inclination to use the military to achieve certain partisan policy objectives.