Immigration and workers' rights advocates protest Donald Trump and other Republican presidential hopefuls outside the Ronald Reagan Presidential Library in Simi Valley, Calif., on Sept. 16. (Robyn Beck/Agence France-Presse via Getty Images)

THE FOREIGN-born share of the U.S. population has doubled in the past three decades and now stands at its highest point in nearly a century. Little wonder, then, that illegal immigration triggers visceral debate and white-hot rhetoric during a presidential election campaign. What may be more surprising is that Americans, by a large majority, continue to oppose mass deportation and to favor allowing undocumented immigrants to remain in the country.

Recent polls reflect the passions and divisions animating the debate — over fencing the southwestern border, birthright citizenship and whether to grant legal status short of outright citizenship to immigrants residing illegally in this country, among other issues. From one survey to another, nuance and numbers vary. But on the bottom line question — should illegal immigrants stay or go? — sizeable majorities say they should be permitted to stay.

That fact underscores the disconnect of Donald Trump, the Republican front-runner, with public opinion, and even with most Republican voters. Mr. Trump’s immigration plan calls for deporting 11 million undocumented immigrants — a forcible mass roundup of humanity on a scale unprecedented in this country — then letting “the good ones” back in.

Aside from the devastating cost — to individual lives, families, communities, major sectors of the economy such as agriculture and hospitality, and America’s image — Mr. Trump’s plan would be overwhelmingly opposed by the American public. In a just-released poll from the Pew Research Center, 74 percent of Americans said undocumented immigrants should be allowed to remain in the country, with slightly less than half of respondents supporting full citizenship. Just 24 percent say they should not be allowed to stay in the country legally.

Majorities of Republicans also balk at mass deportation. In the Pew poll, just a third of GOP respondents said they opposed allowing illegal immigrants to remain in the country. In a poll conducted last month by CNN, Republican support for deportation appeared somewhat greater, but still less than a majority. Most Americans, including Republicans, have little stomach for expelling millions of their neighbors from the country.

The most sensible policy would be to set undocumented immigrants on a long-term path to citizenship, providing they meet certain requirements. What’s sensible may not be what’s doable in Washington, no matter the outcome of the 2016 presidential election. Perhaps more imaginable is a compromise that withholds citizenship but grants undocumented immigrants legal status that allows them to live and work unmolested in this country. Some Republicans will still cry “amnesty,” and some Democrats will cry injustice at creating a cohort of “second-class” Americans.

Yet it’s a good bet that many or most illegal immigrants, drawn to this country primarily by job opportunities and the chance for a better life for themselves and their children, would welcome a new world free from the threat of deportation. Legal status short of citizenship may not be ideal or fair; it would, however, be far more humane and rational than the absurd status quo. Notwithstanding the loudest voices on the campaign trail, polls suggest it also would be welcomed by most Americans.