Dan Driscoll’s departure as Army secretary has brought new scrutiny to the Trump administration’s sweeping changes at the Pentagon, with Democrats and some Republicans warning that Defense Secretary Pete Hegseth’s approach is creating instability among the military’s top leaders.But the president replacing senior military leaders is nothing new. Presidents from Abraham Lincoln to Harry Truman have removed commanders when they lost confidence in their leadership, disagreed over strategy or wanted a different direction.What stands out about the current moment is the pace of the turnover — and th...