John S. McCain, the senator from Arizona whose independent spirit enlivened his campaign for the Republican presidential nomination, delivered the 245th Commencement address. Here are excerpts from his talk:

Thank you. . . .Thank you, distinguished faculty, families and friends, and thank you, University of Pennsylvania Class of 2001. The invitation to give this commencement address is a great honor for someone who graduated fifth from the bottom in the United States Naval Academy Class of 1958. To stand here, in full academic regalia, and address an audience of distinguished academics and their learned students has reaffirmed my long held faith that in America anything is possible.

Leadership or selfishness

…All of you will eventually face a choice, earlier in life than you might now presume, about whether you will become leaders in our society, in commerce, industry, government, the arts, religion, the military, or any integral part of our civilization — or will you allow others to assume that responsibility while you attempt to reap the blessings of a prosperous country without meaningfully contributing to its advancement. I very much hope you will take the first course.

Such responsibility, to be sure, is not always an unalloyed blessing to the person who chooses it. Leadership is both burden and privilege. But as Socrates contended, “the unexamined life is not worth living,” so I contend that the passive life is not worth forgoing the deep satisfaction, the self–respect, that comes from employing all the blessings God bestowed on you to leaving the world better for your presence in it.

No one expects you at your age to know precisely how you will lead accomplished lives or use your talents in a cause greater than your self-interest. You have some time, I’m sure, before such choices and challenges confront you. Indeed, it has been my experience that such choices reveal themselves over time to every human being. They are seldom choices that arrive just once, are resolved at one time, and thus permanently fix the course of your life. Many of the most important choices one must make emerge slowly, sometimes obscurely. Often, they are choices that you must make again and again.

Honor or temptation

…I have always found that the most difficult choices between honor and dishonor occur when no one is watching. For a politician, that presents something of a dilemma. We like to have our virtue affirmed in the public spotlight. But no matter how clever you are in crafting a public image of integrity, if it is a false image, the truth will emerge — and usually sooner than expected.

The lessons I learned as a young man and officer have sometimes helped me withstand the temptations of public life to cut a few corners here and there for the sake of ambition. And sometimes not. I wouldn’t want anyone here to be fooled into thinking that I am the example of rectitude I pretend to be to my children.

But events I have witnessed and the example of others have taught me that it is far preferable in one short lifetime to stick by truths that give more meaning to life than fame or fortune.

God grants us all the privilege of having our character and our honor tested. The tests come frequently, as often in peace as in war, as often in private as in public.

For me, many of those tests came in Vietnam. I knew no one who ever chose death over homecoming. But I knew some men who chose death over dishonor. The memory of them, of what they bore for us, helped me see the virtue in my own humility. It helped me understand that good character is self-respect, and courage and humility are its attributes.

Many years have passed since I learned that lesson. But I have not let the comforts and privileges of my present life obscure the memory of what I witnessed then. And in recent years when I have faced difficult decisions and chosen well, the choice was made easier by the memory of those who once made harder choices and paid a much higher price for the privilege. And when I chose poorly, their example made me ashamed and left me no explanation for my failure other than my own weakness.

A greater cause

When I was a young man, I thought glory was the highest ambition, and that all glory was self-glory. My parents tried to teach me otherwise, as did the Naval Academy. But I didn’t understand the lesson until later in life, when I confronted challenges I never expected to face.

In that confrontation, I discovered that I was dependent on others to a greater extent than I had ever realized, but that neither they nor the cause we served made any claims on my identity. On the contrary, they gave me a larger sense of myself than I had before. I discovered that nothing is more liberating than to fight for a cause larger than yourself; something that encompasses you, but is not defined by your existence alone.

In America, our rights come before our duties, as well they should. We are a free people, and among our freedoms is the liberty to care or not care for our birthright. But those who claim their liberty but not their duty to the civilization that ensures it live a half-life, having indulged their self-interest at the cost of their self-respect. The richest man or woman possesses nothing of real value if their lives have no greater object than themselves.

An unfinished nation

…We are not a perfect nation, a perfect union. Prosperity and power may delude us into thinking we have achieved that distinction, but inequities and challenges unforeseen a mere generation ago command every good citizen’s concern and labor. What we have achieved in our brief history is irrefutable proof that a nation conceived in an idea, in liberty, will prove stronger and more enduring than any nation ordered to exalt the few at the expense of the many or made from a common race or culture or to preserve traditions that have no greater attribute other than longevity.

As blessed as we are, as empowered by liberty as we are, no nation complacent in its greatness can long sustain it. We are an unfinished nation. And we are not a people of half-measures.

I ask you to take your place in the enterprise of renewal, giving your counsel, your labor, your passion in your time to the enduring task of national greatness. Prove again, as those who came before you proved, that a people free to act in their own interests will perceive their interests in an enlightened way, will live as one nation, in a kinship of ideals, and make of their power and wealth a civilization in which all people share in the promise of freedom.

Although you were born in the last century, you will spend most of your life in this one. You are 21st-century Americans. I am not. I don’t know how far humanity will progress in this century, but I expect great things, great things, indeed. I envy you so for the discoveries you will experience. Be worthy of your times and your advantages. Be worthy of your country. Serve a cause greater than yourselves and you’ll know a happiness far more sublime than pleasure.

Will you be tomorrow’s leaders? I don’t know. But I would be proud if you were. You are blessed. Your opportunity is at hand. Make the most of it.