Traveling the country these past five months while writing a book, I’ve had my own opportunity to take the pulse, far from the campaign crowds. My own totally unscientific polling has left me feeling that if there is one overwhelming hunger in our country today it’s this: People want to do nation-building. They really do. But they want to do nation-building in America.

They are not only tired of nation-building in Iraq and in Afghanistan, with so little to show for it. They sense something deeper — that we’re just not that strong anymore. We’re borrowing money to shore up our banks from city-states called Dubai and Singapore. Our generals regularly tell us that Iran is subverting our efforts in Iraq, but they do nothing about it because we have no leverage — as long as our forces are pinned down in Baghdad and our economy is pinned to Middle East oil.

Our president’s latest energy initiative was to go to Saudi Arabia and beg King Abdullah to give us a little relief on gasoline prices. I guess there was some justice in that. When you, the president, after 9/11, tell the country to go shopping instead of buckling down to break our addiction to oil, it ends with you, the president, shopping the world for discount gasoline.

We are not as powerful as we used to be because over the past three decades, the Asian values of our parents’ generation — work hard, study, save, invest, live within your means — have given way to subprime values: “You can have the American dream — a house — with no money down and no payments for two years.”

That’s why Donald Rumsfeld’s infamous defense of why he did not originally send more troops to Iraq is the mantra of our times: “You go to war with the army you have.” Hey, you march into the future with the country you have — not the one that you need, not the one you want, not the best you could have.

A few weeks ago, my wife and I flew from New York’s Kennedy Airport to Singapore. In J.F.K.’s waiting lounge we could barely find a place to sit. Eighteen hours later, we landed at Singapore’s ultramodern airport, with free Internet portals and children’s play zones throughout. We felt, as we have before, like we had just flown from the Flintstones to the Jetsons. If all Americans could compare Berlin’s luxurious central train station today with the grimy, decrepit Penn Station in New York City, they would swear we were the ones who lost World War II.

How could this be? We are a great power. How could we be borrowing money from Singapore? Maybe it’s because Singapore is investing billions of dollars, from its own savings, into infrastructure and scientific research to attract the world’s best talent — including Americans.

And us? Harvard’s president, Drew Faust, just told a Senate hearing that cutbacks in government research funds were resulting in “downsized labs, layoffs of post docs, slipping morale and more conservative science that shies away from the big research questions.” Today, she added, “China, India, Singapore … have adopted biomedical research and the building of biotechnology clusters as national goals. Suddenly, those who train in America have significant options elsewhere.”

Much nonsense has been written about how Hillary Clinton is “toughening up” Barack Obama so he’ll be tough enough to withstand Republican attacks. Sorry, we don’t need a president who is tough enough to withstand the lies of his opponents. We need a president who is tough enough to tell the truth to the American people. Any one of the candidates can answer the Red Phone at 3 a.m. in the White House bedroom. I’m voting for the one who can talk straight to the American people on national TV — at 8 p.m. — from the White House East Room.

Who will tell the people? We are not who we think we are. We are living on borrowed time and borrowed dimes. We still have all the potential for greatness, but only if we get back to work on our country.

I don’t know if Barack Obama can lead that, but the notion that the idealism he has inspired in so many young people doesn’t matter is dead wrong. “Of course, hope alone is not enough,” says Tim Shriver, chairman of Special Olympics, “but it’s not trivial. It’s not trivial to inspire people to want to get up and do something with someone else.”

It is especially not trivial now, because millions of Americans are dying to be enlisted — enlisted to fix education, enlisted to research renewable energy, enlisted to repair our infrastructure, enlisted to help others. Look at the kids lining up to join Teach for America. They want our country to matter again. They want it to be about building wealth and dignity — big profits and big purposes. When we just do one, we are less than the sum of our parts. When we do both, said Shriver, “no one can touch us.”