[4] Three of them were unable to read or write and initially found work as laborers on dairy farms before eventually establishing their own.

[3] Following his graduation, Costa worked as an aide to U.S. Representative John Krebs, assisting in policy matters related to California’s Central Valley.

[5] In 2004, Costa entered the Democratic primary for the 20th Congressional District, which was opened up by the retirement of Cal Dooley, its seven-term incumbent.

Dooley endorsed his chief of staff, Lisa Quigley, as his successor, but most of the state's Democratic Party establishment, including Senator Dianne Feinstein, endorsed Costa, who won the bruising primary and faced Republican state senator Roy Ashburn in November.

[citation needed] The 20th District at the time was a heavily Democratic, 63% Latino-majority district; it gave Al Gore his highest vote total outside the state's two large conurbations (Sacramento and the San Francisco Bay Area in the north and Los Angeles and San Diego in the south).

[citation needed] Costa was re-elected in 2008 with 74% of the vote, the highest percentage for a Democratic incumbent outside Sacramento, the Bay Area, and Southern California.

[9] In November 2011, the League of Conservation Voters ran a series of television ads in Costa's district criticizing his environmental record.

[11] Costa faced an unexpectedly close race in 2014 against Republican Johnny Tacherra, a dairy farmer from rural Fresno County.

[22] For the 118th Congress:[23] Member of the:[24] In 2020, Costa received a 100% rating from NARAL Pro-Choice America[25] and has been endorsed by the Planned Parenthood Action Fund.

[26] Costa opposed the overturning of Roe v. Wade, saying, "this ruling strips women of their freedom to make their own decisions and the constitutional right to privacy.

"[27] He is an original co-sponsor of the Women's Health Protection Act,[28] which prohibits governmental restrictions on the provision of, and access to, abortion services nationwide.

[30] If enacted, the act would reduce transparency by protecting livestock farmers from changes to waste storage and disposal methods.

Admission Act, which would grant statehood to the residential areas of the current District of Columbia as the State of Washington, Douglass Commonwealth.

On February 9, 2023, Costa, along with 30 other Democrats, voted with House Republicans to reject the Revised Criminal Code Act of 2022, passed by the Council of the District of Columbia.

"[35] On October 1, 2020, he co-signed a letter to Secretary of State Mike Pompeo that condemned Azerbaijan's offensive operations against the Armenian-populated Republic of Artsakh, denounced Turkey's role in the Nagorno-Karabakh conflict and called for an immediate ceasefire.

[36] In February 2023, during the Russo-Ukrainian War, Costa signed a letter advocating for President Biden to give F-16 fighter jets to Ukraine.

[37] Costa has been a regular attendee of the Yalta European Strategy annual meetings founded and sponsored by Ukrainian oligarch Victor Pinchuk.

He is an original co-sponsor of the American Dream and Promise Act,[42] which provides a pathway to citizenship for Deferred Action for Childhood Arrivals (DACA) recipients.

He said, "Over my congressional career—through three presidents from both parties—I have continually voted to improve border security, including authorizing construction of physical barriers where appropriate.

[48] In 2021, Costa joined a group of conservative Democrats, dubbed "The Unbreakable Nine", who threatened to derail the Biden administration's $3.5 trillion budget reconciliation package meant to tackle the nation's infrastructure.