Updated: Friday, 12:47 p.m.

Donald Trump tried to reassure his millions of Twitter followers on Thursday that all is not lost. He did so by giving himself a new nickname: Mr. Brexit.

Although he did not explain what parallels he sees between his faltering campaign for the American presidency and the results of the British referendum vote in favor of an exit from the European Union, just minutes later, the London editor of the conservative website Breitbart, Raheem Kassam, suggested that Trump was referring to the surprise victory of the anti-immigrant Leave campaign despite a raft of bad poll numbers.

Kassam did not say if he based this reading of Trump’s tweet on any inside information — but the message was posted one day after the Republican candidate put Breitbart’s chairman, Stephen Bannon, in charge of his campaign.

“Mr. Trump,” Kassam wrote on the Breitbart web site, “is said to believe that the U.S. presidential election is similar to the United Kingdom’s European Union referendum campaign, where pollsters consistently underestimated the Brexit vote, leading to a shock victory for the populist Leave campaigners.”

Although Trump’s current deficit in opinion polls looks far more serious than the numbers for the Leave campaign — which actually led in several surveys — the candidate himself suggested during a visit to Scotland in June, the day after the referendum passed, that his own campaign had tapped into a similar strain of anti-immigrant populism. Ignoring, or unaware of, the fact that a vast majority of Scots had voted to Remain in the E.U., Trump told reporters at one of his Scottish golf courses, “Basically, they took back their country.”

On Thursday, after a pro-Brexit member of Briton’s Conservative party, Daniel Hannan, scolded Trump for his comparison, Breitbart’s London editor argued that the two campaigns were united by a focus on concerns over immigration and national identity.

It is undoubtedly true that the Leave campaign’s principal focus was immigration, certainly in the final weeks before the vote, which is when it started to pull even or ahead in many polls.

As John Lanchester noted in the London Review of Books, the campaign appealed primarily to white working class voters who, with good reason, felt left behind by the increasingly globalized economy, and vented their anger at migrant workers. Trump’s anti-immigrant campaign has been structured like this from the beginning, and he clearly hopes for a similar result.

What that argument overlooks, however, are quite different demographics — and the crucial difference between attitudes about immigration in the two countries.

As a Pew Research Center survey published in July showed, residents of the U.K. were closely divided on the question of whether “having an increasing number of people of many different races, ethnic groups and nationalities in our country” made Britain a better or worse place to live — with 33 percent saying “better” and 31 percent saying “worse”. By contrast, a majority of Americans, 58 percent, said “better,” and just 7 percent said “worse.”

A new Pew poll conducted this week showed that just 16 percent of Trump supporters say that “an increasing number of people of many different races, ethnic groups and nationalities in the U.S. makes the country a worse place to live.”

The Pew surveys also revealed that across Europe, where countries are still defined as nation-states, or primarily homelands for one ethnic group, immigration is seen as negative by large portions of the population, despite the relaxation of internal borders in the E.U.

What is perhaps more telling, for Trump’s desire to cast himself as Mr. Brexit, is that while 13 percent of the population of England and Wales was born overseas in the most recent data — a number comparable to the modern United States — mass migration is much more recent in the U.K. and is seen by some as a threat to older forms of national identity.

On the eve of the referendum vote, the far-right gunman who assassinated Jo Cox, a pro-Europe member of Parliament, shouted “Britain First,” invoking the name of a white nationalist group whose slogan is “Taking Our Country Back!

The overwhelming majority of the white population of England and Wales, 86 percent, has also grown up with the idea that their nation-states, like those in the rest of Europe, are and should be defined along ethnic lines — primarily as the homelands of the English and the Welsh. Majorities in those two parts of the U.K. voted in favor of Brexit.

The United States, in stark contrast, has been a multinational land of immigrants for centuries and attempts to define it as primarily a homeland for white Europeans appeal mainly to a fringe group of white supremacists.

The American electorate is far more diverse than the one that voted, narrowly, for Brexit. As Pew notes, nearly a third of eligible voters on Election Day in November, 31 percent, will be Hispanic, black, Asian or members of another racial or ethnic minority.

And most Americans are also well aware of the fact that they are descended from immigrants. In a new section of census surveys that asks Americans for their ancestry, 80 percent specified which the nations their people came from originally.

Among the largest groups, according to the 2000 census results, were 42.8 million people (15 percent of the population) who considered themselves to be of German ancestry; 30.5 million, or 11 percent, who said their ancestors came from Ireland; 24.9 million, or 9 percent, who traced their origin to Africa; 24.5 million, or 9 percent, who said their people were originally English; 18.4 million, or 7 percent, who said they were Mexican, and 15.6 million, or 6 percent, who said they were Italian.

An interesting anomaly in that census data is that 20.2 million Americans, or 7 percent of the population, when asked where their ancestors were from, answered “America.”

A map released by the United States Census Bureau shows that this group, of Americans who seem to have lost touch with the fact that they, too, are the descendants of immigrants, is clustered in the South, mainly along the Appalachian Mountains — a region that voted heavily for Donald Trump in the Republican primaries.

A Census Bureau map showing the largest self-reported ancestry in each county in the United States.

Trump’s current gambit, to amp up his appeal to the anti-immigrant sentiment of white voters who delivered him the Republican nomination, is based on the idea encapsulated in the Nixonian slogan on the signs held up at his rallies: “The Silent Majority Stands With Trump.” What he might not be aware of is that this slice of the population, which is far from silent thanks to the advent of social media, is also no longer a majority of the electorate.

Top photo: A mural in Bristol, England of Trump sharing a kiss with former London Mayor Boris Johnson, a major Brexit supporter