There are certain documents that constitute the canon of the United States. Though we might disagree on the specific documents constituting this canon, we would probably agree on at least a few of them: The Constitution, the Declaration of Independence, the Federalist Papers and the Gettysburg Address for example.

Enshrined in these documents is great wisdom born of centuries of hard political and philosophical battles. To be fair, there’s also a bit of sloppiness and frustrating over-generalizations. For example, the Constitution says nothing about how many Justices should be on the Supreme Court, or what the Senate’s “advice and consent” is all about. No mention is made, at least in the original, of women, the disabled; of native peoples or gays or even slaves. It doesn’t tell us how to draw up congressional districts or whether to have a capitalist economy that eschews regressive taxes.

Yet rarely, if indeed before or since, has there been a more succinct, valuable and eloquent statement about the loftiest constituting and governing principles to which men might aspire, than the preamble of the Constitution:

“We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.”

It is reasonable to focus on the imperatives of justice, tranquility, defense, welfare and liberty. These elements, perhaps excepting liberty, have been required of governments throughout the ages. Liberty is an exceptional and profound addition to these otherwise classic notions; an addition I have spent some time extolling. But hiding there, right at the beginning, are perhaps my favorite four words of our American canon, “A more perfect union.”

These words embody a concept no less, and arguably even more valuable than the explicit imperatives. Perhaps more important even than the following guarantee of liberty. This is not because those subsequently enumerated demands We the People place on government aren’t of priceless value. Nor because we would ever consider it prudent to excise them from our corpus of laws. Rather, it is because those four simple words look to the future. They embody the notion that perfection is a goal that always lies ahead, that there is always room for improvement.

You see, even if those other ineffable promises weren’t so boldly inscribed, we would still have hope for a better tomorrow. Those four words, “A more perfect union,” are the greatest wellspring of hope imaginable. It is those words that set the United States on a heading toward an ever brighter future. At the time they were written, injustices and horrific denials of liberty were commonplace. The lie was put, immediately and egregiously, to some of the higher ideals of Madison, Washington and company. But those four words set the fuse burning; the fuse that sputtered and sparked until powder-kegs of denied liberties exploded throughout the land and the thunder of justice echoed from coast to coast. Those words are the antithesis of dyed-in-the-wool, stick-in-the-mud, leave-it-well-enough-alone conservatism. They compel change toward perfection. They demand it!

They make any claim regarding the inviolability of the Constitution immediately suspect. They can reasonably be seen as an admission of humility on the part of those tremendously patriotic and intellectually gifted wealthy white men that hammered out the remainder of the Constitution in the summer of 1787. Note that they did not say “The most perfect Union,” or “The perfectly good enough Union,” or even “I suppose it will just have to do Union.” Their Union was simply “more perfect”. More perfect than what had come before: The Greeks, the Romans, the British and the Confederated but self-serving Colonies. But less perfect than was possible. And, tellingly, less perfect than it would become in 1865 when it was re-united without slavery, or 1920 when women were given the right to vote. And less perfect than it became in 1963 when the Supreme Court ruled that all criminal defendants are entitled to legal counsel and that Bible readings should stop being forced upon children in public schools. The same year, 1963, that zip codes would help us communicate more efficiently. And the year Martin Luther King had a dream. A dream, I can unreservedly proclaim, of an even more perfect union.

We live in a country that is built on hope and self-improvement. Of more, and even more, and ever more perfection. From our schools to our courts. From our lofty arts to our heady sciences. From our necessities to our luxuries we have been striving to improve for more than two centuries. We have, and we continue to set an example of what hope and the humility of knowing we’re not ever perfect, coupled with the energy and fortitude to try and do better can do for a people.

We must all do our part to ensure that that this enlightened search for perfection, for our ever more perfect union, continues apace as we face the challenges the future brings.