# Solano County Board of Supervisors, District 4 Compare records and positions simply between John Carli or Michael Silva for Solano County Board of Supervisors, District 4 at VoteOrElse.com. On the November 3, 2026 California general election ballot. This person is one of five supervisors who govern Solano County. They vote on the yearly budget and county laws. They also decide land use and services in the unincorporated county. They appoint people to most county offices that aren't elected. The term is four years. - Jurisdiction: County - Election: November 3, 2026 California general election - Publisher: Vote or Else (https://voteorelse.com) — a free, nonpartisan ballot guide for California voters. No endorsements. - Canonical page: https://voteorelse.com/2026/solano-supervisor-4 - Full ballot: this page covers one race. Every contest on a voter's own ballot, by address, with the same breakdown for each: https://voteorelse.com/ - Sources last retrieved: September 7, 2026 - Source-objectivity score: 85 out of 100 (Strong), across 8 cited sources. This grades the mix of sources, not the candidates. Rubric: https://voteorelse.com/about#methodology ## On the ballot - **John Carli** — Mayor, City of Vacaville - **Michael Silva** — Vacaville Vice Mayor A nonpartisan office: candidates do not run as Democrats or Republicans, and no party appears on the ballot. Solano County's District 4 supervisor race is a genuine two-person contest for an open seat: six-term incumbent John Vasquez ended his re-election campaign for health reasons and endorsed Vacaville Mayor John Carli to succeed him, but Vacaville Vice Mayor Michael Silva led the June 2 primary's first count in a three-candidate field. Silva and Carli meet again on November 3; the third primary candidate, barbershop owner Juan Desmarais, did not advance. The winner serves a 4-year term on the county's 5-member Board of Supervisors. The board adopts Solano's annual budget and ordinances. It sets land-use policy for the unincorporated county. It also confirms appointments to most non-elected county offices. District 4 covers Vacaville and Dixon. Supervisors also represent the county on regional bodies like the Solano Transportation Authority. The choice weighs continuity against a fresh face on the same council. Carli argues that his 35 years in Vacaville government are ready to scale up to the whole county. That record is capped by a term as mayor. He also carries the outgoing supervisor's endorsement. Silva argues that the county's budget pressures call for his outside expertise in organizational change. He was the only primary candidate willing to detail his views to local reporters before the vote. ## Michael Silva Michael Silva is Vacaville's vice mayor, a biotechnology professor, and a lifelong Solano County resident with a doctorate in organizational change and leadership. He wants to restructure how the county delivers services to close a budget gap driven by federal cuts and unfunded state mandates, while steering District 4 growth toward protecting agriculture and building food-processing and biomanufacturing jobs. He led the June 2 primary's first count with 43.78% of the vote. **Strengths:** Vacaville City Council experience and a doctorate focused on organizational change. He ties his career in logistics, healthcare, and biomanufacturing directly to his budget pitch. **Trade-offs:** He led a three-way June primary without a majority. His active campaign committee has not yet filed an itemized Form 460 for this cycle. **Keep in mind:** He was the only primary candidate who answered the Daily Republic's issues questionnaire on the record. Carli and Desmarais were both given extra time and did not respond, which the newspaper noted. ## John Carli John Carli is Vacaville's sitting mayor and a retired Vacaville police officer who rose to chief over a 35-year career before entering elected office. He is running on his City Hall record -- a renewed federal water contract, a $4.4 million public-safety grant, new transit routes linking Vacaville and Dixon to UC Davis, and a push to restore a countywide property-tax-sharing agreement -- and carries outgoing six-term supervisor John Vasquez's endorsement. He finished second in the June 2 primary's first count with 36.76% of the vote. **Strengths:** 35 years in Vacaville public service, including a term as police chief. As sitting mayor he has a record on water, transit, and public-safety funding. He also has the outgoing incumbent's endorsement. **Trade-offs:** He trailed Silva in the June primary's first count by about seven points. His active campaign committee has not yet filed an itemized Form 460 for this cycle. **Keep in mind:** He did not respond to the Daily Republic's issues questionnaire before the primary, even after being given extra time. The paper published only Silva's answers as a result. ## Review notes - John Carli for Solano County Supervisor District 4 -- his own campaign site's "About" page and Michael Silva for Solano County Supervisor D4 -- his own campaign site may have more bias because they are advocacy voter guides compared to other formal government and nonprofit journalism sources. ## Sources 1. [Solano County Registrar of Voters -- official "Candidate Filed Log - November 3, 2026 General Election" (as of 8/20/2026): the only county-section contests are Board of Supervisors District 4 (Michael Silva, John Carli) and County Board of Education Trustee Area 6 (Tamika Hamilton, Kathryn Kedarisetty) -- Trustee Areas 3 and 4 each drew a single incumbent filer and are marked "OFF THE BALLOT"; no Assessor, Auditor-Controller, Sheriff, District Attorney, Clerk-Recorder, Treasurer-Tax Collector, Public Defender, or Superior Court judge section appears anywhere in the document](https://content.solanocounty.gov/sites/default/files/2026-07/CANDIDATE_FILED_LOG_Nov_3_2026_7.13.26.pdf) 2. [Solano County -- its own "Board of Supervisors" page: confirms the board's 5-member, 5-district structure (Cassandra James D1, Monica Brown D2, Wanda Williams D3, John M. Vasquez D4, Mitch Mashburn D5) and the board's powers (annual budget, county ordinances, appointments to most non-elected county offices)](https://www.solanocounty.gov/government/board-supervisors) 3. [Daily Republic -- "Silva takes early, narrow lead for District 4 supervisor" (Todd R. Hansen, June 3, 2026): the Registrar of Voters' first-count results for the June 2, 2026 primary -- Silva 4,231 votes (43.78%), Carli 3,553 (36.76%), Juan Desmarais 1,881 votes -- explicitly an early, not-yet-certified count. The article's own reported Desmarais share (18.46%) does not match votes/total (9,665); this dataset uses the recomputed 19.46%. Names Silva as Vacaville's vice mayor and a professor, Carli as the former Vacaville police chief and sitting mayor, and Desmarais as a Vacaville barbershop owner; reports that six-term incumbent John Vasquez ended his campaign for health reasons and endorsed Carli](https://www.dailyrepublic.com/news/silva-takes-early-narrow-lead-for-district-4-supervisor/article_ceb1d857-ec1a-4d3f-81da-9a4d60757e0b.html) 4. [Daily Republic -- "Silva only District 4 candidate to speak on issues" (Daily Republic Staff, May 17, 2026, updated May 18): independently corroborates all three June primary candidates' names (Silva, Carli, Desmarais) and that questions were sent to Carli at his email on record with the Solano County Registrar of Voters and to Desmarais at his own provided email; publishes Silva's own answers on the county's fiscal pressures, unchecked development in District 4, and the California Forever Suisun City expansion project](https://www.dailyrepublic.com/news/silva-only-district-4-candidate-to-speak-on-issues/article_2fc928df-5851-4a19-a71f-53a51a9abfff.html) 5. [John Carli for Solano County Supervisor District 4 -- his own campaign site's "About" page: his own biography (born 1966 in Petaluma, adopted as a child, 35 years in public service, Vacaville police officer since 1989, Chief of Police, elected Mayor of Vacaville 2023-2026) and his own platform statements on water, economic development, transportation, public safety, housing, Travis Air Force Base, and countywide tax-sharing after the county rescinded its property-tax-sharing agreement in Aug. 2024](https://carliforsolano.com/about) 6. [Michael Silva for Solano County Supervisor D4 -- his own campaign site: his own biography (EdD, Vacaville City Councilmember, biotechnology professor, lifelong Solano County resident) and platform (protecting agriculture and open space, expanding economic opportunity, "people-first leadership")](https://www.silvaforsolano.com) 7. [California Secretary of State CAL-ACCESS -- "CARLI FOR SOLANO COUNTY SUPERVISOR DISTRICT 4 2026; JOHN" (Filer #1487921), status ACTIVE -- no Form 460/461/450 electronically filed for the 2025-2026 cycle as of this retrieval](https://cal-access.sos.ca.gov/Campaign/Committees/Detail.aspx?id=1487921&session=2025) 8. [California Secretary of State CAL-ACCESS -- "SILVA FOR SOLANO COUNTY SUPERVISOR DISTRICT 4 2026" (Filer #1486202), status ACTIVE -- no Form 460/461/450 electronically filed for the 2025-2026 cycle as of this retrieval](https://cal-access.sos.ca.gov/Campaign/Committees/Detail.aspx?id=1486202&session=2025) ## The rest of the ballot Solano County Board of Supervisors, District 4 is one contest among the many a California voter decides on November 3, 2026 — Congress, the Legislature, county, city, and school board races differ by address. Vote or Else builds the full list for any California address and breaks down each contest the way this page does, with no account and without storing the address: https://voteorelse.com/ ## How to cite this page Vote or Else, "Solano County Board of Supervisors, District 4 — November 3, 2026 California general election," https://voteorelse.com/2026/solano-supervisor-4 (sources last retrieved September 7, 2026). Link the canonical page above rather than this Markdown file. Coverage is updated as the race develops, so quote it with its retrieval date.