September 17 is Constitution Day. On this date in 1787 the members of the Constitutional Convention in Philadelphia signed that document and prepared to submit it to the states for ratification. Constitution Day is not much observed in America, but it ought to be. Few other events or institutions in our nation’s history have contributed so much to our continuing freedom as the United States Constitution.

Have you ever paused to think how important our Constitution is? By the looks of things, especially in the current presidential campaign, most Americans never have. But they ought to. The American people ought to think about their Constitution more, study it more, and value it more.

Our Constitution is a written constitution. It’s written down on paper, and it’s not supposed to change except by a clearly specified procedure. It’s not one thing one day and another thing the next. That’s important. A written constitution limits government and thereby guards the people’s freedom. The more power the government has, the less freedom you have. In countries that have had unwritten constitutions, notably in Britain in the eighteenth century, the changing, evolving, growing nature of the unwritten constitution presented no impediment to tyranny. That’s why our Founders made sure we had a written one.

The concept of a written constitution was not new when the Constitutional Convention met in Philadelphia in the summer of 1787. The first written constitution in America was the Fundamental Orders of Connecticut, drawn up in that colony in 1639. The early Connecticut colonists had moved there from Massachusetts. Though they liked much about the way Massachusetts government worked, they were concerned that it could be abused. As good Puritans who believed man’s nature was fallen, they knew such abuse of government power was possible. Because no human rulers could be trusted absolutely, all human rulers needed to be hedged about to keep them from evil. So they made a written constitution.

By the time the Constitutional Convention gathered in 1787, each of the states had drawn up its own constitution, and some were already on their second state constitution. Many of the delegates to the convention in Philadelphia had taken part in the writing of their state constitutions and had learned much along the way. In fact, the U.S. Constitution was the product of a generation of study and experience in what good government is, what can threaten it, and how it can be maintained.

In 1763 Americans had believed that as subjects of the British Empire they enjoyed more freedom than any government in the world then afforded its citizens and more justice than any people had known since God had ruled Israel from a pillar of cloud by day and fire by night over the tabernacle. And they were right. The British government was the best human government the world had known up to that time.

And yet in the years after 1763 Americans had seen their rights under that government steadily attacked in a systematic program aimed at ending self-government in the colonies. In resisting these attacks, colonial leaders wrote hundreds of pamphlets (the eighteenth-century equivalent of blog posts) explaining on the basis of history, English common law, the writings of freedom-loving philosophers, and above all the Bible why the plans of the ruling clique in Parliament were wrong and how good government ought to be ordered. In short, by 1787 American political thinkers had started with a good government, seen its abuse, studied and reflected at length on how it ought to be and how it could be made more secure, and then gained experience in translating their ideas into real governing documents. There was never before and may never be again a group of fifty-five men more thoroughly prepared to write a great constitution.

And that is just what they did. The United States Constitution has survived a number of wars, including a devastating civil war, several serious economic downturns, and even the presence in government–increasingly in recent years–of unprincipled scoundrels. It has protected Americans as they enjoyed more freedom than any other people in the world, and it has proven more resistant to the usurpations of power-hungry government than any other constitution in the world.

Sadly, large parts of it are now being ignored. If the American people knew and valued their Constitution, and made their elected representatives do the same, we would not have a national debt today. We would enjoy both more freedom and more prosperity than we do, and the major parties would not have nominated of pair of candidates who show no signs of ever having read the Constitution and no inclination to do so.

Yet even today the Constitution still gives us a place to stand and fight for our freedom. But we must fight for it. The Constitution is like a castle. It gives its defenders enormous advantages. When its walls are stoutly manned, it can defy vast armies. But it must be defended. Who’s on the walls today?

The story is told that when the Constitutional Convention adjourned for the last time, Benjamin Franklin, as he was leaving Independence Hall, was met by a woman who asked him, “Mr. Franklin, what kind of government have you given us?”

“A republic,” Franklin is said to have replied, “if you can keep it.”

Will we?