The bodies of four American service members killed during the Iran war returned to the United States in flag-draped cases on Wednesday, their families and President Donald Trump looking on.

As he threatens an escalation in the conflict, risking retaliation and further danger to the thousands of American troops arrayed across the Middle East, Trump watched as the human toll of his decisions was transferred from the belly of a military cargo plane, walked across the tarmac at Dover Air Force Base in Delaware and loaded into waiting vans.

Trump saluted, staring straight ahead. The silence of the transfer was pierced only by the plane’s auxiliary engine and a final, anguished wail from a family member stationed opposite Trump on the tarmac. It took just under 20 minutes for the four silver cases to move from the plane to the vans, which drove them away.

Perhaps nothing underscores the weight of responsibility for a president more than traveling to Dover for the solemn ritual. Trump acknowledged as much as he was departing Washington.

“For me, it’s one of the hardest things to do as a president, but has to be done,” he said before taking off on his new, Qatari-donated Air Force One.