For years, left-wing candidates and pundits have complained that the big problem with the Democratic Party is that it just doesn’t energize progressives. The argument goes like this: If you nominate a self-described socialist or a true champion of far-left policies, you’ll mobilize a hidden treasure trove of progressive voters who have been just sitting at home waiting for a “real” progressive to come along—and you won’t even have to talk to a single Trump voter. There’s no doubt we will all see this base-obsessed strategy on full display in this week’s debate, which will feature Democratic presidential candidates leapfrogging each other to the left on almost every issue imaginable. Sen. Bernie Sanders will call for Medicare for All, Julian Castro will pledge to repeal the law that makes unauthorized border crossings a crime and Andrew Yang will extol the virtues of a Universal Basic Income—all with the hope that exciting the base will put them in the White House.

I have just one question for the purveyors of this mobilization theory. Can you give me one example of a competitive election where it’s actually worked?

The United States is in the midst of a crisis. A racist, lying egomaniac is occupying the White House. This simply isn’t the time to bet on an untested hypothesis that sounds good but has never resulted in a real-life win. The stakes are too high. Instead, Democrats should run the 2018 playbook that just delivered House Speaker Nancy Pelosi the gavel and put Democrats in the governors’ mansions of purple and red states from coast to coast. To beat Donald Trump, of course Democrats must mobilize voters. But the party also must persuade voters beyond its base and build a broad coalition—and that base must include some of the folks who pulled the lever for him the first time around.

This isn’t an academic debate. We just had a major test called the 2018 midterms, and the results couldn’t be clearer. Sanders and his allied organizations Our Revolution and Justice Democrats said they were going to use that election to prove their case. They ran a bunch of far-left candidates in Democratic primaries across the country who carried their agenda. Breathless media coverage insisted that revolutionaries like Reps. Alexandria Ocasio-Cortez of New York and Rashida Tlaib of Michigan were taking over the party, and Sanders personally campaigned with congressional candidates who agreed to push his policy agenda. So what happened? Only a third of those candidates could even persuade enough Democratic voters to win their own primary in swing districts. And not a single one of them flipped a Republican seat—in a cycle that saw Democrats gain a total of 41.

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