Rep. Karen Bass (D-CA) has overtaken billionaire developer Rick Caruso in the primary race for mayor of Los Angeles, thanks to vote-by-mail that has led to an eight-point swing in the results.

Caruso, a Republican-turned-independent-turned-Democrat, is running as a political outsider promising to fix homelessness and crime in the city. Bass, a left-wing activist-turned-Washington insider, is the favorite of the party establishment.

On Election Night, Caruso had more votes, leading Bass by a proportion of 41% to 38%.

In the week since, that proportion has reversed itself. The Los Angeles Times reported Tuesday evening:

Rep. Karen Bass pulled ahead of rival Rick Caruso in the primary election for Los Angeles mayor on Tuesday after a surge of vote-by-mail ballots boosted the congresswoman and several other progressive candidates.

Over the last week, a flood of late-arriving mail ballots propelled left-of-center candidates in races for mayor, city attorney and multiple council seats.

At one point, Caruso even led by five percentage points, meaning that vote-by-mail has brought about an eight-point swing.

It is unclear who will emerge as the final winner, and it is unclear whether vote-by-mail always favors the left-wing candidate. The Times notes: “Riverside and Orange counties have seen ‘red shifts’ as more votes have come in, but in San Francisco, the election to recall Dist. Atty. Chesa Boudin has narrowed since election day.”

Regardless, the shift in L.A. underscores the power of Bass’s turnout machine, and the great challenge that faces Caruso in the general election.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News and the host of Breitbart News Sunday on Sirius XM Patriot on Sunday evenings from 7 p.m. to 10 p.m. ET (4 p.m. to 7 p.m. PT). He is the author of the recent e-book, Neither Free nor Fair: The 2020 U.S. Presidential Election. His recent book, RED NOVEMBER, tells the story of the 2020 Democratic presidential primary from a conservative perspective. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. Follow him on Twitter at @joelpollak.