Reaffirming our nation’s independence

The Fourth of July, Independence Day, is a good time not only for hot dogs and fireworks, but to reflect for a moment on what makes this country unique, the qualities that enabled it to become in some ways the most successful country in history, and to contemplate the extent to which those qualities still animate Americans.

It has been said that the United States is the only country founded on an idea, or a set of ideas, rather than on ethnic or racial similarities, kinship, conquest or...