At just over 50 words, the Preamble to the U.S. Constitution has been memorized by American elementary students in huge numbers. But how many of them actually understand its meaning? Despite its brevity, the introduction to the most important document in the nation's history hides some important details that make America unique in its government and ambitions.

What's the Big Idea?

The Preamble begins with the phrase, "We the People of the United States..." This immediately declares that the government shall be one of the people, to be led and served by its own citizenry, rather than a detached aristocracy. The introduction also defines the purposes of the Constitution, which includes establishing justice, promoting domestic peace and securing the "Blessings of Liberty." Since its ratification in 1788, this powerful paragraph has served as the first words of an ambitious vow to "form a more perfect Union."