Biden’s weakness after a distant second finish in Nevada could have compelled Californians who have been voting since the Iowa caucuses to support a moderate alternative who was doing better at the time. But there’s a big upside for Biden: A huge number of them haven’t voted yet. The portion of returned ballots at this stage is much lower than in recent elections — and his campaign is counting on a late surge of support among those holdouts after his dominant performance on Saturday.

Paul Mitchell, an elections expert who has tracked the number of returned vote-by-mail California ballots through Friday, told POLITICO he’s seen a significant drop-off among Democratic voters to date from the last two California presidential primaries. And the decline in returned ballots so far is occurring among the most dedicated voters: Those who have participated in the last five elections.

“People in Super Tuesday states and California, in particular, are not returning their ballots yet,” Danielle Cendejas, a Democratic strategist in California whose firm did campaign mail for both of Barack Obama’s presidential campaigns.