This has rarely been a tranquil nation. Born in revolution, tested by civil war, energized by protest, the United States has survived turmoil even as it has pursued its constitutional mandate to ensure tranquillity. Today, that elusive sense of domestic peace is tested by new challenges, chief among them persistent poverty and the fraying of our connective infrastructure.

No less than James Madison, the Constitution's principal author, saw the dangers inherent in a society that treasured equality but practiced inequity. Shay's Rebellion in 1786-87 rattled Madison with its armed assault on the wealthy, and the man who helped create this nation's legal architecture eloquently worried about those "who will labour under all the hardships of life, and secretly sigh for a more equal distribution of its blessings."

Shay's Rebellion has receded into the corners of the national memory; the Depression gave way to war and jobs; the Great Society came and went. But inequality continues to tug at the American conscience. In our land of opulence, poverty and decay upset our peace.

Poverty

If tranquillity is best assured by "a more equal distribution" of the nation's wealth, we have much to fear. Our schools are faltering; our healthcare system leaves millions without access to doctors. Many are homeless or face the loss of homes. Some seethe at illegal immigrants who compete with Americans for jobs. In our America, 60 million people survive on $7 a day.

As we contemplate the coming election, we seek a president who understands that the unchecked spread of poverty is not a natural condition but rather a failure of government, and that action is required. Democrat John Edwards has been the most ardent anti-poverty crusader in the campaign; his ideas include strengthening labor laws, stimulating job creation and distributing housing vouchers for poor families that could be used anywhere, not just in government housing. The latter proposal alone would vastly expand shelter for those in need. The rest of the Democratic field offers little in the way of ingenuity, opting instead for the obvious observation that money spent in Iraq could better help America's poor.

On the Republican side, lack of specificity is matched by conspicuous indifference. When the GOP candidates were invited to debate poverty at Morgan State University in September, not one of the then-front-runners attended; present were Mike Huckabee, Duncan Hunter, Sam Brownback, Tom Tancredo, Ron Paul and Alan Keyes. Now a leading contender, Huckabee frames fighting poverty as a "pro-life" position; more constructively, he also addresses issues such as prison reform. Other Republicans have done meaningful anti-poverty work -- John McCain in housing and Mitt Romney in healthcare.

Although these candidates present ideas that might contribute at the margins, none goes far enough. Here are some ideas we'd like to hear them discuss:

* President Bush came to office on a promise of "compassionate conservatism," but in housing, as in so many other areas, he's proved far more conservative than compassionate. His administration has sought, for instance, to cut Section 8 housing vouchers by 850,000; his successor should not only replenish the voucher program but add to it. There is no poverty worse than homelessness.

* The next president should support and pay for early childhood programs such as Head Start; he or she also should endorse tax breaks for college students and their parents. Low-income students would benefitif community college tuition, in particular, were tax-deductible. And here's a proposal we would welcome: federal assistance for states educating the majority of the nation's illegal immigrants. Education can lift a poor person into prosperity; the government owes its people this chance to raise themselves.

* Free trade is an engine of growth and jobs and thus opportunity. Yet open markets bring dislocation, and for the worker whose plant moves to Mexico, it is cold comfort that jobs are being created abroad. For Democrats especially, this last issue is a trying one. President Clinton was a champion of free trade and a supporter of NAFTA -- this page supported it then and still does. Today's candidates, however, are less enthusiastic. Edwards blames the pact for sending 1 million jobs abroad. Sen. Barack Obama calls for it to be "renegotiated." Sen. Hillary Rodham Clinton says it should be "fixed." Rep. Dennis J. Kucinich veers into absurdity by proposing to scrap NAFTA and withdraw from the World Trade Organization.

Our goal should not be to abandon free trade but rather to make it work -- for the economy and also for the poor.

Infrastructure

In August 2005, Hurricane Katrina slammed into the Gulf Coast, and New Orleans was ravaged. Katrina is now a byword for federal incompetence, and properly so. Though state and local governments bear their blame too, the 53 levees that failed belonged to the national government. The response was shamefully overseen by the Bush administration, and the victims overwhelmingly were poor. It fell not to a politician but to a poet to capture that spectacle: "Thems got, got out of town. Thems who ain't, got left to drown." (Bruce Springsteen, regrettably, is not a candidate.)

Last year it was a bridge that failed -- Minnesota's I-35W, an eight-lane, 1,900-foot span over the Mississippi River. When it fell, 13 died. Suddenly, a report on the nation's bridges by the American Society of Civil Engineers gained new relevance: One-quarter of our almost 600,000 bridges are functionally obsolete.

And yet with few exceptions, the candidates have offered little beyond platitudes. They want strong bridges and levees but, for the most part, are silent about how to pay for those priorities. We want a president whose commitment is commensurate with our history. The federal government linked our coasts by rail and gave us our highway system, projects that enjoyed broad support and reaped historic benefits; it should rebuild those connections and encourage Internet access as we redefine our infrastructure.

Unfortunately, Democrats in this too often play to their base, and Republicans too readily think cheap.

At a debate sponsored by the AFL-CIO, Democrats acted as if the problem of falling bridges was mainly one of jobs -- welcome words for their hosts, if not exactly on point. Still, there are hopeful signs. Sens. Clinton and Christopher J. Dodd are cosponsors of legislation that would create a National Infrastructure Bank, to be financed through long-term public bonds sold to investors. Clinton also has a worthy plan to spend $10 billion on bridges and other infrastructure and $250 million in grants for states to conduct emergency reviews, as well as increased federal funding for public transit and support for broadband initiatives.

To the extent that they address it at all, Republican front-runners discuss infrastructureas a matter of national defense. Romney last month created the Romney for President Homeland Security Policy Advisory Group, a council to advise him on border, infrastructure and transportation security. Rudolph W. Giuliani gives lip service to infrastructure repair but seems afraid for anyone to think he might spend money on it. Paul breaks away from the conventional; he argues for privatizing maintenance of roads and collection of tolls. His proposal is more philosophical than real.

It is often said, with good reason, that this is a wealthy and generous country. But when millions live in hunger, when bridges fall, it is hard to sustain our pride. The next president owes the nation the stability for which Madison yearned.

Next: "The Common Defense" explores U.S. power and prestige. The complete "American Values" series can be found at latimes.com/values08.