Most speeches, happily, are over when they are over. Once over, they get ignored. Not so Senator Marco Rubio’s recent “Common Good Capitalism.”

The Senator chose The Catholic University of America as his venue, and he makes a decent effort to draw on Catholic Social Teaching. At its center, as Rubio’s title acknowledges, is the common good.

Of special note: He cites Pope Emeritus Benedict XVI’s charge that the economy too often centers on largely speculative financial flows rather than on real production. Rubio, to his credit, insists that the economy must serve the nation and not the reverse. Citing John F. Kennedy, he also argues that culture and economics are indivisible.

Still, I’d give the speech only two cheers. Why so? The senator unabashedly supports “American Exceptionalism.” A phrase, to be sure, is just a phrase. As such, it’s neither true nor false. What the Senator vigorously maintains is that “American Exceptionalism both exists and is a very good thing.”

For a start, though, we can’t know that any such thing exists unless we know what it is. The Puritans didn’t talk about it. Alexis de Tocqueville, the acclaimed student of American life, never spoke of it.

Lo and behold, it was old Joe Stalin who first used the phrase. It was a handy way to refer to the revisionism of Communists who held that America’s prosperity made it an exception to the Marxist timetable for class struggle and revolution. Stalin, of course, disagreed.

Well, then, somebody needs to fill in the blank. “American Exceptionalism is ____________.” Three contenders come to mind. It’s the thesis that America is (1) the most powerful country in the world, (2) the leader of the free world, (3) the moral beacon of the nations. None of these contenders is promising.

The U.S. might well be the most powerful country in the world. Times change, though. Once England ruled the waves, and long ago the Roman Empire held sway. There’s no reason to think that the U.S. will continue to be the most powerful country, and there’s good reason to think that might doesn’t make right.

Perhaps, though, the U.S. is the leader of the free world. But it is not its destiny to be such, and it will be so only if it remains free. Power, we know, tends to corrupt. In any case, being the leader of the free world is a contingent rather than an essential property of the U.S.

Is the U.S., then, the moral beacon of the nations? Let’s look at the record, as Gov. Al Smith liked to say. Over the past four decades, it has legally sanctioned some 60 million abortions. Recently the ahistorical construct of “same sex marriage” has become a civil right. Its government resolutely stockpiles nuclear weapons. There is a huge disparity in the distribution of goods and resources. No, the U.S. is far from being a moral beacon.

There is, though, one way to make sense of American Exceptionalism. This way enables us to affirm both that it exists and that it is a good thing. Suppose that the people of this country share a commitment to the common good, understood as integral human development. Such a commitment, if it is the fruit of both our history and our vision, would express our vocation. It is a vocation, nonetheless, that is open to every people that orders itself to the common good. St. John Paul II gave witness to this exceptionalism when he bent over to kiss the soil of each nation that he visited.