The 2016 primaries produced an unusual dilemma for those accustomed to setting the parameters of acceptable liberal opinion in American politics. Marginal and demoralized for decades, left politics suddenly came roaring back thanks to Bernie Sanders — whose popular message struck a resounding chord within the Democratic base despite the centrist preferences of the party’s establishment.

What were the guardians of liberal opinion, so used to dictating what ordinary voters were allowed to expect and demand, to do?

Liberalism Inc. never quite settled on a unified answer, cycling instead through an endless series of meta-arguments for why Sanders and/or his policies, popular as both were, were ill-suited to Democratic Party and the country. The arguments are too numerous to list, but many shared the same basic feature: nominal endorsement of Sanders in principle coupled with outright rejection of him in practice.

Arguments in this vein paired abstract statements about what was desirable with dogmatic assertions about what was possible (which usually, for their authors, turned out to be very little). Put another way, liberal writers kept discovering ever-more innovative ways to explain why policies like single-payer health care — however popular, and as much as they’d personally like to see them happen — just weren’t realistic, and why the only person advocating them would somehow make a bad candidate for president.

Now, more than two years after the supposedly more electable politician’s defeat at the hands of the least popular Republican in polling history, Sanders is running again and some are intent on replaying the old formula for 2020.

Fresh out of the gate is commentator Eric Alterman, who last week published a short essay called “The Liberal Case Against Bernie.” True to form, the piece runs through a laundry list of partisan grievances against Sanders, some of them unbelievably petty (Alterman complains about Sanders’s recent hiring of two journalists on the grounds that both have deigned to criticize other candidates and their policies on Twitter, something supporters of other Democrats running for president evidently never do).

More to the point, Alterman swings dizzyingly between associating himself with Sanders’s views and implying they’re a poison pill that will as good as guarantee Trump’s re-election. “A dangerous lunatic is president of the United States and Sanders, of all the major Democratic contenders, is the one who will make Donald Trump’s reelection most likely,” he writes, before continuing:

Let me clarify: I’ve been a fan and supporter of Sanders ever since he was elected mayor of Burlington, Vermont, in 1981. I was honored to be asked to testify before him in Congress years ago, and I voted for him in the New York presidential primary in 2016. I did so, however, not because I imagined he might win the nomination, but because I hoped that a strong showing by Sanders would help wake up Hillary Clinton to the importance of addressing economic inequality, and also to honor his brave criticism of Israel’s occupation of the West Bank.

Having aligned himself with Sanders’s politics, Alterman proceeds to deem them too revolutionary, noting the Vermont Senator’s radical history and explicit identification with socialism. It fast becomes unclear in the ensuing morass of red-baiting where his own criticisms stop and those of the hypothetical Republican attack ads he insists would sink a Sanders presidential campaign begin:

Sanders was still a socialist in 1980, when he served as an elector for the Trotskyist Socialist Workers Party, which favored the abolition of the US military budget and proclaimed itself in solidarity with both Cuba and Iran at a time when the latter held over 52 Americans hostage. I held some of the same views myself as a young man, but I am not running for president. And if I ever thought I might, I probably wouldn’t have agreed to attend a rally in 1985 in Managua, Nicaragua, with a crowd chanting, ‘Here, there, everywhere, the Yankee will die,’ while the Nicaraguan president, Daniel Ortega, condemned my country’s ‘state terrorism’ (accurate as the term was). [emphasis added]

Amusingly enough, Alterman goes on to claim Sanders’s views on the Israel-Palestine conflict (views which he himself lauds only a few paragraphs above in the same essay) will make too many people “uncomfortable,” also flagging the threat of a Howard Schultz spoiler campaign as another reason to oppose a Sanders nomination.

Tortured as Alterman’s whole narrative is, its recurrence in various forms since 2016 illustrates a deeper rot in the way some liberals have come to think about American politics after decades of dominance by the Right. Whether we take such arguments in good faith or not, their implications remain profoundly conservative — essentially precluding ambitious efforts from the left of any kind, even when the available evidence suggests they’re both immensely popular and electorally viable. Given that such efforts are bound to provoke a backlash of one kind or another — from insurance companies, from corporate America, from the Republican Party — Alterman is as good as saying that these should be allowed to limit the terms of liberal and left opposition and their horizons of possibility.

Bernie Sanders’s candidacy has much to commend it, but among its most significant postures is a refusal to engage in the politics of preemptive capitulation still wrongly touted by some liberals as a regrettable political necessity.

After all, why surrender when you can fight?