In May 1940, Lord Halifax urged Winston Churchill to call for a national day of prayer to aid in the evacuation of the troops in Dunkirk.

The historic event grounding Christopher Nolan’s Dunkirk involved a military crisis that was, in its beginning, as dark, desperate, and seemingly hopeless as it was extraordinary, full of heroism, and even miraculous in its conclusion. Whether his film captures any of that sufficiently is an open question.

The huge IMAX theater in Washington, DC where I watched Dunkirk was packed with young people. Out of hundreds in…