The Democrats’ Age Divide Is Defining the 2020 Primary

When the progressive tag team of Senator Bernie Sanders and Representative Alexandria Ocasio-Cortez skirmished with Joe Biden this week over climate policy, the altercation pointed toward the former vice president’s most glaring vulnerability in the 2020 Democratic presidential race—while simultaneously underscoring the imperative for him to defend his greatest asset.

Biden’s most obvious weakness in the crowded contest is that his centrist instincts and policy record, particularly during his 36-year-long Senate career, are likely to regularly spark conflict with younger progressives such as Ocasio-Cortez who are growing far more assertive in the party. His greatest strength is his appeal to older Democratic voters, both white and African American, who are typically more ideologically moderate and more politically pragmatic. For the 76-year-old Biden, that’s an acceptable trade-off because voters older than 45 cast fully 60 percent of all votes in the 2016 Democratic primary, according to a cumulative CNN analysis of all the exit polls conducted that year.

It’s not hard to see that Biden would seek a “middle ground” on climate policy—as a preview of attacks he’ll face from more liberal 2020 rivals on many aspects of his record, including policies on and . In turn, it’s not hard to predict that those challenges may cause the biggest problems for Biden among younger voters, who were far more likely than older generations to describe themselves as very liberal in the 2016 Democratic primaries, according to the CNN analysis.