Historians flatter themselves that if people understood the past they would know how to act in the present, self-important reasoning utterly belied by the fact historians don't all vote the same way. The problem is that our imperfect glimpses of the past seldom afford us the opportunity to make firm conclusions about history, let alone to derive clear lessons from it. I prefer to think that history's lessons are of a more general sort, so please indulge me as I don my robes, assume my position behind the podium, and convey three lessons about American history that I think every American ought to know.
First: Americans have never agreed about how their country ought to be governed, how it should conduct itself in the world, or what their foundational documents mean. These matters have been the subject of incessant debate since the Continental Congresses met in Philadelphia - before there even was a United States. There never has been an American consensus, there has been a series of compromises. The Constitution of 1787 itself was the result of compromises that fully satisfied none of its authors, and those compromises have been the beating heart of the great republic and its ongoing revolution for 232 years. Only once did the constitutional order fail to yield a working compromise — in 1861 — and then over the one issue about which compromise was not possible. It is therefore altogether wrong for Americans to bemoan "partisan politics", for such politics have been a vital part of American life from the beginning. It is doubly wrong to impugn a fellow citizen as "un-American" without very good cause, for it presumes that there is one archetype of an American citizen, one correct interpretation of the Constitution, one indisputable version of what America means. There is not. There never has been. Such things alluded the Founding Fathers themselves.
Second: the American Revolution was not merely political, but also intellectual. Thomas Jefferson spoke five languages, and lived a life of ceaseless critical inquiry into the great questions of philosophy, politics, science, and religion. Should you accept less from your leaders today?
Third, and above all, the person who you choose to be your President — and in any given Presidential election, only about half of you bother to make a choice at all — affects not just the United States but the whole world. It is of no particular consequence to anyone other than Canadians who the Prime Minister of Canada happens to be. But individual Presidents have changed the world; the choices made by Wilson and Roosevelt and Johnson and Reagan had reverberations that were felt — indeed, are still felt — by every living person on the face of the Earth. Remember always that your right and duty to choose your chief executive is a duty to humanity as a whole.
And, finally, my sincere good wishes, my American friends, on this, the 232nd birthday of your country.