Well, not the current president, but the LA Times has this about FDR:
Sixty-three years ago this week, as Allied troops stormed the beaches of Normandy in World War II, President Franklin D. Roosevelt led the nation in an extraordinary moment of mass prayer.
“Almighty God,” Roosevelt said as millions of Americans gathered around their radios June 6, 1944, “Our sons, pride of our nation, this day have set upon a mighty endeavor, a struggle to preserve our republic, our religion, and our civilization, and to set free a suffering humanity.”
It is not unusual for presidents to mention God, or to encourage Americans to offer up prayers for a cause. But experts on Roosevelt and the role of religion in politics note that the “D-day Prayer” is distinctive. Here was a president asking the public to join him in a prayer of his own composition.
The day after D-day, which set the stage for the liberation of Europe, the New York Times reported that the prayer “had been sent out throughout the country and printed in newspapers so that the millions who listened to the broadcast could recite the words with the president as he spoke.”
According to the Franklin D. Roosevelt Presidential Library and Museum in Hyde Park, N.Y., the White House released the text in the afternoon and Roosevelt delivered the prayer at 10 p.m. Eastern time.