I keep asking myself why our country is so divided. Why our dialogue on the critical problems that threaten us is so shrill, so brittle and so unproductive. Why we take refuge in nonsense rather than doing the hard work of reasoning together that is now required of us.

We Americans have had profound divisions before. The framers of the Constitution were so divided over slavery that only an awkward compromise allowed the United States of America to be born. “Four score and seven years” after the Declaration of Independence, that festering boil erupted into the Civil War. We had persisting divisions over the role of business, trusts and labor from about 1875 through the first decades of the 20th century. We were deeply divided over the Vietnam War in the 1960s and ’70s. In the case of past internal conflicts, the geographic and economic power and the isolation of the United States meant that we had the time to work through political fault lines at our own speed.

That’s no longer the case. We’re now part of a global economic web that we helped build, but whose consequences we understood poorly. And this largely unregulated planetary economy careers forward with or without us.

What’s most dangerous today about our national polarization is that the public has lost confidence in the institutions of governance that will be needed to overcome it. This fuels extremism, that combustible mix of delusion, demonization and despair. If things are going badly, such thinking goes, do I trust my own instincts or public institutions? If I’m told government is bloated, misguided or in the hands of self-dealing incompetents, it’s easier to vilify those who disagree with me.

For three decades we glorified “the market,” and in the name of that false god, large-scale, legal bribery in the Congress led us to loosen or remove the checks and oversight that once limited abuse in the financial system. Some banks peddled predatory mortgages, some companies were given loopholes that allowed them to pay no taxes, we cut revenue and borrowed to make it up — and finally the bubble of phony credit blew up in our faces.

Barack Obama was elected on a wave of desperate hope, but the fractured political landscape did not foster the “let’s work together” trust he asked for. And the new hit-and-run, demonizing digi-media have for the time being advantaged narrow political assault and diluted thoughtful, fact-based dialogue. It is a strange and explosive world of public debate in which the president’s health care proposal could have been seriously alleged to rely on “death panels.”

What or who will lead us out of this morass? One possibility is for an experienced, trusted national figure to emerge — possibly a centrist Republican. But how would he or she get nominated in today’s Republican Party? Is there a new generation of young voters emerging that can rebalance our political equation so that we once again become pragmatic, constructive, innovative, non-ideological and confident? Will continuing economic hardship allow a dramatic leader on the model of FDR to emerge — someone who, like Franklin Roosevelt, is strong enough to dramatize the way forward, ridicule the liars and hatemongers, and summon us to discipline and sacrifice?

We have been lucky, we Americans, at finding a Washington or a Lincoln or a Roosevelt when we really needed them.

We really need one now. By definition, the new course will incur the wrath and demagoguery of the vested interests that have fattened like maggots off the excess and dishonesties of the past decade. It will take someone extraordinarily gifted, uncompromisingly honest, and blessed with lively communication skills to outline and rally us to the new road forward. And in contrast to past periods of division and doubt, this time we have to get our act together quickly, or the rest of the world will move ahead without us.

Peter Goldmark, a former publisher of the International Herald Tribune, headed the climate program at the Environmental Defense Fund. He wrote this for Newsday on Long Island, N.Y.