How has support for Katie Porter and Eric Swalwell changed over time in California polls since August 2025?

1. The August baseline: Porter as the early Democratic leader

In August and into mid‑November, several polls found Porter leading the Democratic field and the broader primary with roughly mid‑teens support—most notably a UC Berkeley/LA Times snapshot that put her at about 17% in August before October’s controversies ^[1], and a PPIC mid‑November topline that listed Porter at 21% in a broader 16‑name list taken before later entrants ^[4].

2. The October–November slide: video hits and declining numbers for Porter

After widely circulated video clips and staff complaints about Porter’s behavior, at least one major poll recorded a drop from 17% in August to 11% by late October, a four‑point decline observers linked in reporting to those negative revelations ^{[1] [5]}. Local coverage and analysts framed that slump as making Porter vulnerable and inviting new challengers ^{[6] [1]}.

3. Swalwell’s entry and the December shakeup

Eric Swalwell’s decision to enter the race late produced a rapid reallocation in multiple December surveys: Emerson’s Dec. 1–2 snapshot showed Swalwell at roughly 12% to Porter’s 11% in the full field ^{[2] [3]}, while Emerson’s internal Democratic‑only breakdown had Swalwell at 20% to Porter’s 17% among Democrats in one release, indicating he immediately split and in some measures overtook her base support ^{[7] [2]}.

4. Poll-to‑poll divergence: FM3, Emerson, Newsweek and others

Not all polls tell the same story: FM3 found Democratic voters preferring Swalwell 30% to Porter 21% in a Democratic sample but put Porter at a higher 13% in one likely‑voter topline, while Emerson and Newsweek summaries alternately list Porter between 9% and 11% and Swalwell near 12% in various full‑field readouts ^{[8] [9] [2]}. This spread reflects differences in likely‑voter screens, question order and timing—polls taken before or after high‑profile moments diverge materially ^{[8] [2]}.

5. Favorability and unfamiliarity: context that makes small changes look big

Emerson’s detailed metrics show Porter with a 30% favorable and 34% unfavorable rating and 37% of respondents unsure or never having heard of her, while Swalwell carried a 24% favorable, 23% unfavorable, and a majority (53%) saying they were unsure or had not heard of him—figures that mean small swings in name recognition or news coverage can produce outsized movement in headline support ^[2].

6. How much is true movement versus noise?

Multiple outlets note a large undecided pool—Emerson put undecideds at roughly 31%—and margins of error that make the upper‑tier candidates effectively tied; that suggests at least part of the apparent Porter decline and Swalwell rise is reallocation within a crowded, volatile field rather than a decisive, permanent realignment ^{[2] [6]}. Where reporters attribute Porter’s slide to oppo and viral moments, partisan outlets frame the same data as Democratic infighting or as a Republican windfall—highlighting interpretive agendas in coverage ^{[10] [11]}.

7. Bottom line and reporting limits

The evidence since August 2025 shows Porter falling from mid‑teens to low‑double digits while Swalwell, entering later, captured roughly the same share or slightly more in several December polls; however, poll variance, large undecided shares, and differences in methodology complicate a definitive trendline, and public polling snapshots do not definitively show long‑term voter consolidation for either candidate ^{[1] [2] [3]}. This analysis is limited to the cited polls and reporting and cannot assess later shifts or internal campaign data not published in those sources.