Bernie Sanders’s Biggest Problem Isn’t Socialism

It’s his disdain for his country. That’s the lesson Democrats should draw from Corbyn’s catastrophe.

With America’s Democrats on the cusp of nominating Bernie Sanders, they have one last chance to look across the Atlantic for a glimpse of how this could end up.

The warning comes via the British Labour Party’s historic defeat in December’s general election. Under Jeremy Corbyn, a leader uncannily similar to Mr. Sanders in ideology, affect and career trajectory, Labour suffered its worst drubbing since 1935. This despite Mr. Corbyn’s adroitness at rallying a youthful and fervent-to-the-point-of-derangement base, the likes of which British politics has rarely if ever witnessed. Ahem.

The conventional interpretation is that it’s Mr. Corbyn’s socialism what done it. He promised a wholesale re-nationalization of the British economy—utilities, transportation, even the internet. He promised an outsize expansion of the state, and outsize tax hikes to pay for it. Those taxes, voters soon noticed, would fall heavily on the middle class, not only the rich.

All that played a role in Labour’s drubbing, but economics may not have been decisive. Polling by YouGov before the election found voters trusting Labour more than the Conservatives on health policy and education, less on taxation, and roughly the same on unemployment.

This angle needn’t worry Mr. Sanders much. Unlike Americans, British voters had labored under the yoke of democratic socialism within living memory. It wasn’t a positive experience for them, and it prompted their turn to Margaret Thatcher and free-market reform in 1979. Mr. Corbyn pledged to take the U.K. back to a past Britons would rather forget.

Mr. Sanders has the luxury of campaigning for socialism in a country that has never tried it. He can present his program as a door to a fabulous new future. U.S. voters still frustrated with the economy for various reasons might be tempted to knock on that door, not understanding what lurks on the other side.

The Corbyn warning for Democrats takes a different form. What British voters really, really didn’t like about Mr. Corbyn wasn’t his economics. It was his culture.

To a remarkable extent the December election wasn’t a vote on Brexit or socialism or Prime Minister Boris Johnson’s economic “leveling up” of poorer regions. It was a referendum on Mr. Corbyn’s Britishness: Does he have enough of it, yea or nay?

Nay, said voters in Labour’s traditional heartlands. Michael Ashcroft, a former Conservative deputy chairman and veteran pollster, this month released a postmortem on Labour’s campaign. His surveys and focus groups with former Labour voters who defected in 2019 are devastating. “He is not patriotic,” one participant said of Mr. Corbyn. “He meets all those terrorist parties. You want someone with good old values.” Quoth another: “He said he would never press the [nuclear] button. We need protection. He should have said he would, even if he didn’t mean it.”

Among those who voted Labour in 2017 but not in 2019, the most common reason for switching allegiance, cited by 53%, was that they didn’t want Mr. Corbyn to be prime minister. That sentiment outranked Brexit as a motivation even among voters who defected to Mr. Johnson’s get-Brexit-done Conservatives by 75% to 73% (respondents could choose more than one option). These voters decided the election.

Mr. Corbyn had given them ample reason for doubt: There was his tendency to pal around with terrorists who killed Britons or their allies. His indulgence of anti-Semitism in Labour’s ranks, which offended working-class Britons’ sense of decency. His disdain for alliances such as the North Atlantic Treaty Organization and military programs such as the Trident nuclear deterrent, which give the U.K. its esteemed place in the world.

Mr. Sanders faces the same problem. No one who shares Middle America’s core values of freedom, democracy and entrepreneurship would choose to honeymoon in the Soviet Union. No one who values American achievements in science, the arts or education would heap praise on Cuba’s schools.

Every other Democratic candidate on a debate stage with Mr. Sanders has been able to communicate even the most fantastical policy ideas with an undertone of patriotism. Mr. Sanders alone sounds as if he wants to replace America rather than transform it.

And if he wins the Democratic nomination he’ll be running against Donald Trump, whose only consistent mode is American greatness. Mr. Corbyn ran aground against a candidate in Boris Johnson and a policy in Brexit that spoke directly to British patriotism.

British voters concluded that the danger of a leader who didn’t share their values was greater than the risk even of Brexit. Labour now faces years in the political wilderness as it tries to rebuild the trust of those who came to doubt whether it’s truly a British party. Democrats still have a chance, barely, to spare themselves that misery.