Tuesday was a bad day for Bernie Sanders. The Vermont senator lost decisively to former Vice President Joe Biden in Michigan, Missouri, and Mississippi. Sanders is falling behind in the delegate count, and in 25 primaries and caucuses so far, he has managed to crack 37 percent of the vote in only three, even as the field has narrowed. This low ceiling is the story of his demise. Sanders hasn’t just failed to bring millions of new voters into the process, as he promised. He has also failed, in state after state, to broaden his share of the existing Democratic electorate.

If you look back at Sanders’ share of the vote in each primary, he hasn’t actually lost ground. In Iowa and New Hampshire, he got a quarter of the vote. In Nevada, he got a third. In South Carolina, he got a fifth. On Super Tuesday, he stayed in the same range, drawing about a quarter of the vote in the states he lost and a third of the vote in the states he won. What hurt him was that Biden increased his share of the vote, while Sanders didn’t. As other candidates dropped out, their voters went to Biden, not Sanders. And one reason for this pattern is Sanders’ constant message of antagonism. He has cultivated enemies instead of friends. Now he’s paying the price.

For months, Sanders has talked about “taking on the Democratic establishment.” He ran on that message in Iowa and New Hampshire. Then, after becoming the front-runner, he went around the country boasting that his critics were right to fear him. At a rally in California on Feb. 17, he gloated that his enemies were “trembling” and “crying on television.” On Feb. 21, the day before he won the Nevada caucuses, he tweeted, “I’ve got news for the Republican establishment. I’ve got news for the Democratic establishment. They can’t stop us.”

Running against the establishment is standard populism. But to win with that message, you have to define the enemy narrowly. The more people you denounce as part of the establishment, the more you scare politicians and voters. If you’re proposing single-payer health insurance, for example, the smart move is to stipulate that you’re just targeting insurance companies. Instead, Sanders has threatened the whole medical sector. “We will take on the health care industry,” he vowed at a rally last week. On Monday, he repeated that line to a crowd in St. Louis. On CNN, he blasted the industry for supporting Biden: “The health care industry that is taking out their checkbooks? That is the establishment. We are taking them on.”

Sanders also attacks the press. Voters don’t care about the press, but they get antsy when a candidate sounds paranoid. Instead of playing to reporters’ liberal sympathies, Sanders depicts them as puppets of “the corporate media.” He accuses them of “freaking out” over his success and hurling “venom” at his campaign. Last week, when MSNBC’s Rachel Maddow pressed Sanders about his failure to turn out new voters, he insisted he was doing well, given that he was “taking on the corporate media.”

Running against the establishment is standard populism. But to win with that message, you have to define the enemy narrowly.

Sanders’ first defeat, on Feb. 29 in South Carolina, was a warning that he needed to assuage fears about his candidacy. Instead, he celebrated those fears as proof of his success. On March 1, he proudly told a crowd in San Jose, California, that the turnout at his rallies was alarming the establishment. The next day, in St. Paul, Minnesota, he repeated that message. When Sanders was informed that fellow candidates Pete Buttigieg and Amy Klobuchar were dropping out and endorsing Biden, he said it was no surprise, since the corporate elite was out to get him. And when Maddow asked Sanders whether he was specifically running against “the Democratic Party establishment”—not just a generic “political establishment”—he replied: “Democratic establishment. Yes.”

At his rallies, Sanders has continued to call for a “political revolution.” And he has added another villain to his list of enemies: the stock market. When the market surged after Super Tuesday, Sanders, far from welcoming this news, cited it as evidence of Biden’s corruption. “We’re taking them all on,” he said of the companies whose valuations had increased. “The stock market went up this morning ’cause they thought that Biden did well.” Sanders told Maddow that “the health care industry and the drug companies did very well” because “Biden had a good day.” And he warned these companies that if he got his way, their stocks would suffer. “I got some bad news for those guys,” he said. “Don’t count your chickens until they’re hatched.”

It’s one thing to run against the greed of certain companies or CEOs. It’s another to root against whole sectors of the stock market, in which most Americans are invested. Sanders comes across as a guy who’d rather hurt capitalists than welcome a boost for 401(k)s. And this reinforces the damage he has done to himself, gratuitously, by insisting that he’s a “democratic socialist.” It’s hard to broaden your support when you seem more interested in ideology and punishment than in whether your attacks on the system are helping ordinary people outside your base.

Meanwhile, Sanders has escalated his talk of conspiracies. On Sunday, he claimed that “the establishment put a great deal of pressure” on Buttigieg and Klobuchar to “force” them out of the race. “What was very clear from the media narrative and what the establishment wanted,” he told George Stephanopoulos, “was to make sure that people coalesced around Biden and try to defeat me.” On Wednesday, after his defeats, Sanders again rebuked “the Democratic establishment” and insisted that “our campaign has won the ideological debate.”

What Sanders fails to understand is the connection between his defeats and his rhetoric. It wasn’t the media or the Democratic National Committee that turned Buttigieg, Klobuchar, and millions of voters against him. It was Sanders. His relentless message of conflict, along with his expanding list of putative enemies, attracted a fraction of the electorate but alienated everybody else. As the primaries narrowed to a two-man race, his base was no longer enough to win. The establishment didn’t destroy Bernie Sanders. He destroyed himself.

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