I am convinced that this kind of nation-building at home is exactly what Mr. Obama is trying to deliver, and should be his unifying call: We need universal health care because it would strengthen our social fabric and enable our businesses to better compete globally. We need to upgrade our schools because no child in 21st-century America should be left behind and because we cannot compete for the best new jobs without doing so. We need a greener economy, not just to mitigate climate change, but because a world growing from 6.7 billion people to 9.2 billion by 2050 is going to demand more and more clean energy and water, and the country that develops the most clean technologies is going to have the most energy security, national security, economic security, innovative companies and global respect.

But to deliver this agenda requires a motivated public and a spirit of shared sacrifice. That’s where narrative becomes vital. People have to have a gut feel for why this nation-building project, with all its varied strands, is so important  why it’s worth the sacrifice. One of the reasons that independents and conservatives who voted for Mr. Obama have been so easily swayed against him by Fox News and people labeling him a “socialist” is because he has not given voice to the truly patriotic nation-building endeavor in which he is engaged.

“Obama’s election marked a shift  from a politics that celebrated privatized concerns to a politics that recognized the need for effective government and larger public purposes. Across the political spectrum, people understood that national renewal requires big ambition, and a better kind of politics,” said the Harvard political theorist Michael Sandel, author of the new best seller  “Justice: What’s the Right Thing to Do?”  that calls for elevating our public discourse.

But to deliver on that promise, Sandel added, Obama needs to carry the civic idealism of his campaign into his presidency. He needs a narrative that will get the same voters who elected him to push through his ambitious agenda  against all the forces of inertia and private greed.

“You can’t get nation-building without shared sacrifice,” said Sandel, “and you cannot inspire shared sacrifice without a narrative that appeals to the common good  a narrative that challenges us to be citizens engaged in a common endeavor, not just consumers seeking the best deal for ourselves. Obama needs to energize the prose of his presidency by recapturing the poetry of his campaign.”