Joe Biden called on Bernie Sanders to accept greater accountability for tactics and rhetoric of his staunchest supporters and do more to discourage it, after what he called the “outrageous” threats on a prominent union that criticized his healthcare plan.

Representatives of the powerful Culinary Workers Union, which represents 60,000 workers supporting Nevada’s gaming and hospitality industries, said this week that supporters of the Vermont senator had “viciously attacked” its members after its leadership warned about the risk to their negotiated health plans under a Medicare for All system.

In an exclusive interview airing Sunday on NBC’s “Meet The Press,” Biden said the Vermont senator “may not be responsible for it, but he has some accountability.”

“You know me well enough to know if any of my supporters did that, I’d disown them. Flat disown them,” Biden said. “The stuff that was said online. The way they threatened these two women who are leaders in that Culinary union. It is outrageous. Just — just go online.”

In 2020, a third name has surfaced, offered as a cautionary tale to a Democratic party that this week confirmed a septuagenarian radical socialist and longtime backbench rebel as its frontrunner. That name is Jeremy Corbyn.

“I don’t want the Democratic party of the United States to be the Labour party of the United Kingdom,” James Carville, the victorious manager of Bill Clinton’s 1992 campaign, told audiences on cable TV and in New Hampshire this week, warning that if Democrats nominate Bernie Sanders, they will almost certainly be following Corbyn’s Labour party to defeat.

On the US campaign trail, journalists, strategists for rival Democratic candidates, and even the occasional voter cite Corbyn in the case against Sanders, offering the result of December’s UK general election as evidence. A week spent in New Hampshire watching the Vermont senator and his opponents do battle provides some answers to the question many US Democrats are asking themselves: is Sanders fated to be America’s Corbyn – or are the two men, and their two situations, radically different?.....

The similarities between the men are obvious. Both spent decades on the political margins, regarded as perennial troublemakers with no prospect of gaining national power. To their critics, they remain stubbornly stuck in the 1970s; to their admirers, they have stayed unwaveringly true to their principles. They both exude a rumpled authenticity, their appearance – Sanders’ wayward hair, Corbyn’s beard – visible proof that they are not careerist politicians of the usual stripe.

Their messages are similar too. Sanders wants “an economy that works for all, not just the 1%”, while Corbyn stood as the champion of “the many, not the few”. Both are exponents of a particular brand of leftwing populism, offering themselves as tribunes of the hard-working majority against an elite of bankers and billionaires that has rigged the economy in its own favour.

Sanders’s explanation of why this is not a problem is simple, and he has repeated it endlessly. When a member of the Los Angeles Times editorial board asked him whether “a candidate as far to the left as you” would “alienate swing voters and moderates and independents,” the senator replied: “The only way that you beat Trump is by having an unprecedented campaign, an unprecedentedly large voter turnout.” Faiz Shakir, Sanders’s campaign manager, adds: “Bernie Sanders has very unique appeal amongst [the younger] generation and can inspire, I think, a bunch of them to vote in percentages that they have never voted before.”

This has remarkably little empirical support. Take the 2018 midterm elections, in which the Democrats took back the House (a net 40-seat gain), carried the House popular vote by almost nine points and flipped seven Republican-held governorships. Turnout in that election was outstanding, topping 49 percent — the highest midterm turnout since 1914 and up 13 points over the previous midterm, in 2014 — and the demographic composition of the electorate came remarkably close to that of a presidential election year. (Typically, midterm voters tend to be much older and much whiter than those in presidential elections.) This was due both to fewer presidential “drop-off” voters (people who voted in 2016 but not 2018) and to more midterm “surge” voters (those who voted in 2018 but not 2016)…..

This analysis shreds an implicit assumption of Sanders and other members of the turnout-will-solve-everything crowd: that if they polarize the election by highlighting progressive issues, “their” nonvoters will show up at the polls, but none of the nonvoters from the other side will. That view is also contradicted by many political science studies. Stanford political scientists Andrew Hall and Daniel Thompson, for example, studied House races between 2006 and 2014 and found that highly ideological candidates who beat moderates for a party nomination indeed increased turnout in their own party in the general election — but they increased the opposition turnout even more. (The difference was between three and eight percentage points.) Apparently, their extreme political stances did more to turn out the other side to vote against them than to turn out their own side to vote for them.

The turnout equation does not necessarily return positive results for a candidate like Sanders. The reverse is more likely. It is truly magical thinking to believe that, in a highly polarized situation, only your side gets to increase turnout. And if the other side turns out in droves, you might not like the results — a warning Democrats would be wise to heed.

U.S. Rep. Joe Cunningham, one of only two Democratic congressmen from South Carolina, forcefully rebuked U.S. Sen. Bernie Sanders on Wednesday, jolting the state’s “First in the South” presidential primary race just hours after the Vermont senator won in New Hampshire.

In a statement to The Post and Courier, the first-term congressman from Charleston said he does not plan on making an endorsement ahead of South Carolina’s Feb. 29 primary but will “defend our Lowcountry values of opportunity, pragmatism and common sense.”

“South Carolinians don’t want socialism,” Cunningham said. “We want to know how you are going to get things done and how you are going to pay for them. Bernie’s proposals to raise taxes on almost everyone is not something the Lowcountry wants and not something I’d ever support.”....

Other candidates have long warned that they believe Sanders would have a damaging effect on down-ballot races if he is the Democratic nominee at the top of the ticket in November.

Former Vice President Joe Biden, who remains the front-runner in South Carolina, has most explicitly made that case, arguing Sanders would hurt vulnerable Democrats in competitive districts like Cunningham as they try to win re-election.

In 2018, Cunningham flipped a seat that had been held by Republicans for four decades in large part by casting himself as a moderate Democrat who would look out for the district over partisan politics.