Caine, a three-star general whom Trump has praised since at least 2019, helped lead an operation in Iraq against the Islamic State during Trump’s first term.

The general made an impression in 2018 when he said, according to the president, that the Islamic State could be defeated in a week.

Defense Secretary Pete Hegseth on Monday rejected a reporter’s question that suggested President Trump’s pick for the new Joint Chiefs of Staff chairman, Dan Caine, was not qualified