I refer to the well-known difficulties American workers face in a globalized economy, problems we share with most postindustrial democracies, such as widening income inequality and the failure of our schools to equip citizens for the unforgiving dynamism of a tech-driven economy and liberalized trade. That these difficulties seem disproportionately to affect white working-class men or rural communities in “red” counties does not mean they are now confined, or will remain confined, to those demographic categories. They are American problems that also affect people of color and other key Democratic constituencies, and they will only intensify as intelligent machines play a greater role in our economic future.

A good campaign might also tackle foreign affairs and defense policy (long overdue for Information Age reform) without widening social and cultural fissures. Yes, we are confronted with substantive, thorny conflicts of interest among our people. This cannot be denied. But there are also truly national interests at stake that provide an ample basis for a more unifying politics. The candidate who gets it right might win big — and set an invaluable, constructive precedent.

If, on the other hand, Mr. Trump’s successors refuse to speak to the whole of the country, it is only a matter of time before another irresponsible figure, right or left, will knock together a winning political combination based upon resentment and unrealizable (or irrelevant) aims. The specter here is neither neo-fascism nor green socialism, but demagogy and enfeeblement as it proves impossible to govern this country merely in the interest of ad hoc constituencies.