When upstart settlers of the New World proclaimed their independence in 1776, they represented but 13 small and fractious colonies carved from a vast wilderness and surrounded by hostile powers.

Two centuries later, the United States of America is the wealthiest, most powerful nation in the world -- and a beacon of freedom to the world. It's a remarkable success story, but success did not come easily.

The young nation endured a devastating Civil War. It emerged stronger than ever, with the blessings of freedom and equality extended to those who had been enslaved.

Generations later, it fought and triumphed in two world wars, spreading democracy among foreign lands. And 20 years ago, the fall of the Berlin Wall marked the successful conclusion of the Cold War against worldwide communism.

How to account for this monumental success?

Every nation derives meaning and purpose from some unifying quality -- ethnic character, common religion, shared history. America is different. Unique among nations, America was founded, at a particular time, by a particular people, on the basis of a particular idea.

At its birth, this nation justified its independence by asserting truths said to be self-evident, according to "the Laws of Nature and Nature's God." Working from the great principle of human equality, the men who launched this experiment in popular government claimed a new basis of political legitimacy: the consent of those governed.

Through a carefully written constitution, the founders created an enduring framework of limited government based on the rule of law. With this structure, the founders sought to establish religious freedom, provide for economic opportunity, secure national independence and maintain a flourishing society of republican self-government -- all in the name of the simple but radical idea of human liberty.

The founding of the United States was indeed revolutionary, but not in the sense of replacing one set of rulers with another or overthrowing the institutions of society. What was revolutionary were the ideas upon which the new nation would be built: permanent truths "applicable to all men and all times," as Abraham Lincoln later said. The ultimate ground of government would be principle rather than will.

To this day, the principles proclaimed in the Declaration of Independence and put into action by the Constitution still define us as a nation and inspire us as a people. And they are responsible for our unmatched prosperity and justice.

Unfortunately, few of our learned elites -- especially our university professors who teach the next generation, shape popular culture and set the terms of political discourse -- teach the self-evident truths that animated the founders. Instead, they passionately embrace and pass on a more "modern" belief: No such truths exist. Certainly no truths applicable to all time, anyway.

That belief now infects our federal government. Today our government acts with little regard for limits placed upon it by the Constitution, which many regard as obsolete. On both the left and the right, political leaders increasingly are unsure of their way. They speak in inspiring generalities, mired in small-minded politics and petty debates.

Amid many challenges -- unsustainable federal spending and skyrocketing debt, the future burden of entitlement programs, national security in a dangerous world -- the real crisis that tears at the American soul is not a lack of courage or solutions. From the decline of civic education to the rise of dependency on government, our societal problems are rooted in a deep confusion about the meaning of America's core principles.

Do we still hold these truths? Do the principles that inspired the American founding retain relevance in the 21st century? We will find it impossible to know what to do and how to do it as long as we aren't sure who we are and what we believe.

We must restore the founding principles as the central idea of our nation's public philosophy. But before we can rededicate ourselves as a nation to these principles, we must rediscover them as a people.

Only then can we renew America and reclaim our future.