WASHINGTON — We now know, or will soon, who won the fiercely contested midterm elections, but we also know who lost: We all did. This election has been a referendum on President Trump, which suits both Republicans and Democrats just fine. Democrats are betting that the public has increasingly tired of Trump’s lies and his vile style. Trump and his supporters believe that Democrats are again underestimating his popular appeal.

What’s been missing is any realistic engagement with the difficult issues facing the country. In democracies, elections serve not only to select the country’s leadership. They also aim to gauge public opinion on the hard issues and to see whether some sort of consensus is possible. The present campaign has featured very little of this constructive politics.

What are some of the hard issues? There’s no secret.

Start with budget deficits. In fiscal 2018, the gap between federal spending and revenues was $782 billion, nearly 4 percent of gross domestic product (GDP). That’s up $116 billion from 2017. Based on current spending and taxes, the Congressional Budget Office expects large deficits forever.

With a 3.7 unemployment rate, no one can attribute these deficits to a weak economy. Put simply, Americans want more government benefits and services than they’re willing to pay for in taxes.

Next, there’s immigration. The “wall” is a symbol for both sides. Opposition allows Trump to accuse Democrats of favoring “open borders,” raising the specter of a country overrun by foreigners. For pro-immigration groups, the wall symbolizes the simplicity and cruelty of Trump’s policies, highlighted by the separation of children from parents.

Finally, global warming. For many Americans, this is the great moral issue of our time. But their fervor is not a policy, and the target of preventing global warming from exceeding 1.5 degrees Celsius (or 2.7 degrees Fahrenheit), measured from the pre-industrial era, is enormously difficult — probably impossible.

What these three issues have in common is this: They’re all politically explosive.

Take the budget. To eliminate the existing deficit would require tax receipts to increase by nearly 25 percent. Or we could reduce spending by a similar amount — that’s nearly $800 billion. The cut would exceed all military spending. Of course, we could also do nothing and gamble that permanently large deficits won’t someday cause a huge financial crisis.

All the choices are bad. We should be debating the role of government and how it can be financed. Instead, our political leaders are making proposals that would worsen deficits. Trump backs more tax cuts; Democrats advance expensive new health benefits and guaranteed jobs for all.

Or consider immigration. As a society, the United States has a decent record in assimilating millions of newcomers. But — as today’s turmoil demonstrates — too much immigration can fracture society and radicalize politics. The magnitude of immigration is undeniable. One in four people living in the United States is either an immigrant (41 million, 13 percent of the population) or the U.S.-born child of immigrants (37 million, 12 percent), reports a study by the National Academies of Sciences, Engineering and Medicine.

Against that backdrop, reasonable compromises should be possible. We ought to be debating the terms: a path to citizenship for most of today’s illegal immigrants; some sort of wall; strict penalties on employers for hiring illegals; a switch from family connections to skill-based immigration.

Similarly, any realistic effort to deal with global warming would be difficult and, quite probably, unpopular. Stabilizing the atmospheric concentration of carbon dioxide would require replacing virtually all fossil fuels (oil, coal, natural gas), which now supply roughly four-fifths of the world’s energy. Prices would rise; and government regulations would become more intrusive.

Candor would have compelled our political leaders to warn us that sensible policies — on the budget, on immigration and even climate change — require patience and sacrifice. We no longer have the luxury of simply ignoring what we don’t like or what we find inconvenient or expensive.

This is, of course, among the hardest challenges facing democracies: to accept short-term costs for long-term gains. Under the best of circumstances, it would be difficult to achieve. Politicians want to win. By and large, they tell voters what voters want to hear, even if it is exaggerated, selective or dishonest.

But the fixation on Trump and his antics turned a longshot into an impossibility. It destroyed the prospects of anything resembling rational debate. Indeed, public opinion may be worse informed at the end of this campaign than at the beginning. In this sense, the campaign may have been wasted.

Robert Samuelson is a columnist with The Washington Post.

Robert Samuelson