From the debate stage in Des Moines, Iowa, on Tuesday night, Massachusetts Sen. Elizabeth Warren activated her closing strategy to lock up the Democratic nomination for president. There's no way to tell if it will be successful, and many reasons to be skeptical that it will. But it may well be Warren's most plausible path to the nomination.

In 2020, the Democratic Party is extremely broad in ideological terms. At one extreme, a lifelong democratic socialist who talks of "political revolution" (Vermont Sen. Bernie Sanders) is proposing programs that would cost untold trillions of dollars in new spending to implement, while also advocating a complete reversal of direction in foreign policy from the consensus that has prevailed in Washington for many years.

At the other extreme, former Vice President Joe Biden, South Bend Mayor Pete Buttigieg, and Minnesota Sen. Amy Klobuchar advocate slightly varying modes of continuity with the Democratic Party's pragmatic conventional wisdom both at home and abroad. Further out toward the leftward edge of the Republican Party, Michael Bloomberg hopes to use his personal fortune to pull the Democrats to the right.

That's an awfully big tent. It's hard to see how Sanders could placate voters who incline toward Biden, let alone Bloomberg, just as Bernie enthusiasts will be exceedingly unlikely to rally around a center-left nominee.

That's where Warren comes in. She's clearly situated herself between these extremes — though she just as clearly wants to be perceived as closer to the left than the center. She showed no signs of changing that approach on Tuesday.

In the lengthy foreign policy discussion that took up the opening half-hour of the debate, Warren positioned herself right next to Sanders, even going so far as to advocate pulling all American troops out of the Middle East. That's a stance that places her far outside of the centrist foreign policy consensus in both parties.

On the revamp of the North American Free Trade Agreement (called the United States-Mexico-Canada Agreement, or the USMCA), Sanders staked out the left-wing-ideological-purity position, claiming to support what's in it (which several major unions have endorsed) while nonetheless promising to vote against it because it doesn't include an adequate statement of principles about fighting climate change. The more centrist candidates all support it, and so did Warren, who nonetheless made a point of throwing some sharp digs at NAFTA in the name of defending American workers.

The pattern repeated itself on health care, child care, and student loan debt — with Sanders defining the left, Biden, Buttigieg, Klobuchar, and billionaire Tom Steyer staking out positions closer to the center, and Warren defining herself as just slightly less left-wing than Sanders.

If that were the entirety of Warren's appeal, it would be a pretty weak bid for party unity. But it had one more component that came to the fore in the highly anticipated exchange roughly halfway through the debate when she and Sanders were asked about Warren's claim that Sanders told her during a private conversation in December 2018 that a woman couldn't win against President Trump. Sanders flatly denied he said any such thing, and Warren replied by pivoting to a passionate defense of a woman's ability to prevail — against Trump or anyone else.

Warren is hardly the first Democrat to use an appeal to identity politics to advance her prospects, though she may be the first one to attempt it in precisely this way. More commonly, Democrats gesture toward the left on social and cultural issues to burnish their progressive credentials while supporting more moderate policies on economics and foreign affairs. But Warren appears to be deploying it in order to energize well-educated, suburban female voters who might otherwise be put off by how progressive she is on economics and foreign policy.

It's a bold move — saying, in effect: "Yes, I'm a lot like Sanders, but I'm also a woman who will fulfill your dream of vanquishing the misogynist in the White House and replacing him with someone who, despite my left-wing agenda, is like you." That Sanders has a (to my mind, unearned) reputation for mild sexism only helps to make the case that he can't possibly satisfy that distinctive urge among Democratic women. Warren's refusal to shake Sanders' hand at the conclusion of the debate signals even more sharply that this is the way in which she plans to differentiate herself from him: not on policy but on identity.

The final piece of the plan came into focus in Warren's closing statement, where she used her upbringing in Oklahoma and the fact that two of her three brothers are Republicans to go a few steps beyond Sanders' own longstanding strategy of making the broadest possible populist appeal to the electorate. It was a bid to pilfer some Trump voters — and especially female Trump voters — for herself and the Democratic Party. That's what she was getting at in her stated aim of uniting not just "as Democrats" but also "with independents and Republicans."

It was abundantly clear by her words and actions Tuesday night that Warren is betting big on unity, while attempting to define herself as the very slightly less extreme, female version of Sanders. The question now is this: Will her strategy work?

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