Elizabeth Warren thought there was no real chance that Sen. Bernie Sanders would run for president. Throughout 2017 and 2018, she and her advisers believed that Sanders would survey the landscape and decide that his biggest contribution could be as kingmaker in a primary, one that would be fought out on terms that he himself had established, with nearly every candidate embracing Medicare for All, a Green New Deal, and a robust role for government that would have been unthinkable just four years earlier, before his 2016 campaign put it all on the map. When Warren and Sanders got together at her apartment in October 2018 for what would become an infamous meeting, Sanders still hadn’t decided whether he was going to run but was laying the groundwork nonetheless. It wouldn’t be her last miscalculation.

The Massachusetts senator jumped in on New Year’s Eve, and signs of trouble emerged early. The email list she had been building since her 2012 Senate campaign produced an anemic fundraising haul, raising just under $300,000 in 24 hours. Former Rep. Beto O’Rourke, by comparison, brought in more than $6 million the first day. Nevertheless, a year after her meeting with Sanders, she was the party’s frontrunner for president, steadily climbing in the polls through the summer until she eclipsed former Vice President Joe Biden. The clear frontrunner at the October 15 debate, Warren took it from all sides, but none more damaging than the barrage from former South Bend Mayor Pete Buttigieg, who attacked her for not having a plan to “pay for” the Medicare for All proposal she endorsed. “We heard it tonight: a yes or no question that didn’t get a yes or no answer,” he said. “Your signature, senator, is to have a plan for everything. Except this.”

'Your signature, Senator, is to have a plan for everything. Except this.' — Watch @PeteButtigieg call out @ewarren for her approach to health care #DemDebate pic.twitter.com/0y3mLchhpU — NowThis (@nowthisnews) October 16, 2019

Warren was trying hard not to give an answer she thought would be kryptonite in a general election — that taxes might go up for the middle class — and so she focused on overall costs instead. “We can pay for this. I’ve laid out the basic principles,” she said. “Costs are going to go up for the wealthy. They’re going to go up for big corporations. They will not go up for middle-class families. And I will not sign a bill into law that raises their costs, because costs are what people care about.” Sen. Amy Klobuchar, teaming up with Buttigieg, compared Warren unfavorably with Sanders — who at the time wasn’t seen as a threat, having just emerged from a Las Vegas hospital after a heart attack. “At least Bernie’s being honest here and saying how he’s going to pay for this and that taxes are going to go up. And I’m sorry, Elizabeth, but you have not said that, and I think we owe it to the American people to tell them where we’re going to send the invoice,” Klobuchar said. Later that night, news broke that Rep. Alexandria Ocasio-Cortez would be endorsing Sanders, followed soon by Reps. Ilhan Omar and Rashida Tlaib, giving Sanders support from three of four members of the so-called Squad and rejuvenating his campaign. On November 1, Warren responded to the pressure to have a plan to pay for Medicare for All by releasing one. Health care activist Ady Barkan hailed it as “perhaps the greatest feat of public policy jujitsu that I have ever seen,” while Sanders supporters online slammed it. Matt Bruenig, writing in Jacobin magazine, helped set the tone, matching Barkan’s hyperbole and dubbing it “a disaster.” His precise objection was narrow — Warren included a head tax on employers, which Bruenig argued should be temporary and slowly transitioned to a traditional payroll tax, while Warren’s plan stipulated it would be permanent. The gap between the genuine objection and the volume at which her plan was criticized became a theme for the next month. Two weeks later, she announced that she would use a legislative process known as reconciliation to implement a public option in her first year and then, once support had been built for a larger public role in health care, she would push for Medicare for All in her third year. Sanders, meanwhile, said he would introduce a Medicare for All bill immediately and challenge opponents in their home districts. By now, Sanders was rising, consolidating much of the left, and Warren was falling, taking on a reputation as a politician who responds poorly when attacked. The Medicare for All rollout mingled with lingering concerns about how she had buckled to President Donald Trump’s taunts and taken a DNA test in 2018. The dagger, though, had been stuck in by the New York Times, the same outlet whose positive coverage helped Warren rise through the summer. On November 4, the paper ran a survey it had done finding that Warren performed relatively poorly against Trump in the must-win Rust Belt states — losing by 6 points to him in Michigan, while tied in Pennsylvania and Wisconsin, a worse performance in all three than either Biden or Sanders.