President Donald Trump’s proclamation that Sunday, September 3, shall be a National Day of Prayer for the victims of Hurricane Harvey follows a tradition first established by George Washington and continued by presidents including Abraham Lincoln and Ronald Reagan, as well as being ratified by Congress. “No people can be bound to acknowledge and adore the Invisible Hand which conducts the affairs of men more than those of the United States,” Washington declared in his first Inaugural Address, the first words uttered by a president of the United States. John Adams succeeded Washington as America’s second president, and he proclaimed...