Some conservative commentators may feel inclined to spend Presidents Day ruminating over Barack Obama's evil intentions, or denouncing the chief executive as an alien interloper and ideologue perversely determined to damage the republic. Instead, they should consider the history of John Adams's White House prayer and develop a more effective focus for their criticism.

On Nov. 2, 1800, a day after he became the first president to occupy the newly constructed executive mansion, Adams wrote to his wife Abigail: "I pray Heaven...