The US Senate career of Kamala Harris began on January 3, 2017, and ended with her resignation on January 18, 2021, to become Vice President of the United States under President Joe Biden. A member of the Democratic Party, Harris defeated another Democrat in the 2016 election to serve as the junior U.S. senator representing California, alongside Dianne Feinstein.

Harris was the first South Asian American U.S. senator and the second Black woman after Carol Moseley Braun. She was first the Black and South Asian American to represent California in the Senate, the second Asian American after S. I. Hayakawa, and the third woman after Feinstein and Barbara Boxer, Harris' predecessor. As a senator, Harris advocated for stricter gun control laws, the DREAM Act, federal legalization of cannabis, Medicare for All, and reforms to taxation. She gained a national profile while asking pointed questions of officials in the first administration of Republican president Donald Trump during Senate hearings, including Trump's second U.S. Supreme Court nominee, Brett Kavanaugh. In 2019, GovTrack designated Harris as the "leftmost Democratic senator".

Harris sought the 2020 Democratic presidential nomination in 2019, but withdrew from the race before the primaries. Biden selected her as his running mate; their ticket defeated the incumbent president and vice president, Trump and Mike Pence, in the 2020 presidential election. During Harris' vice presidency, she cast more tie-breaking votes than any other vice president under the office's role as President of the United States Senate. Her votes passed the American Rescue Plan Act of 2021 and Inflation Reduction Act of 2022.

2016 election to the US Senate

After more than 20 years as a U.S. senator from California, Senator Barbara Boxer announced on January 13, 2015 that she would not run for reelection in 2016. Harris announced her candidacy for the Senate seat the next week. She was a top contender from the beginning of her campaign.

The 2016 California Senate election used California's new top-two primary format, where the top two candidates in the primary advance to the general election regardless of party. On February 27, 2016, Harris won 78% of the California Democratic Party vote at the party convention, allowing her campaign to receive financial support from the party. Three months later, Governor Jerry Brown endorsed her. In the June 7 primary, Harris came in first with 40% of the vote and won with pluralities in most counties. Harris faced representative and fellow Democrat Loretta Sanchez in the general election.

On July 19, President Barack Obama and Vice President Joe Biden endorsed Harris. In the November 2016 election, Harris defeated Sanchez with over 60% of the vote, carrying all but four counties. After her victory, she promised to protect immigrants from the policies of president-elect Donald Trump and announced her intention to remain attorney general through the end of 2016. Harris became the second Black woman and first South Asian American senator in history.

Election results

Tenure and political positions

As a senator, Harris advocated stricter gun control laws, the DREAM Act, federal legalization of cannabis, and healthcare and taxation reforms. She became well known nationally after questioning several Trump appointees such as Jeff Sessions and Brett Kavanaugh.

2017

On January 28, after Trump signed Executive Order 13769, barring citizens from several Muslim-majority countries from entering the U.S. for 90 days, she condemned the order and was one of many to call it a "Muslim ban". She called White House Chief of Staff John F. Kelly at home to gather information and push back against the executive order.

In February, Harris spoke in opposition to Trump's cabinet picks Betsy DeVos for secretary of education and Jeff Sessions for United States attorney general. In early March, she called on Sessions to resign, after it was reported that Sessions, who had previously said he "did not have communications with the Russians", spoke twice with Russian ambassador to the United States Sergey Kislyak.

In April, Harris voted against the confirmation of Neil Gorsuch to the U.S. Supreme Court. Later that month, she took her first foreign trip to the Middle East, visiting California troops stationed in Iraq and the Zaatari refugee camp in Jordan, the largest camp for Syrian refugees.

In June, Harris garnered media attention for her questioning of Rod Rosenstein, the deputy attorney general, over the role he played in the May 2017 firing of James Comey, the director of the Federal Bureau of Investigation. The prosecutorial nature of her questioning caused Senator John McCain, an ex officio member of the Intelligence Committee, and Senator Richard Burr, the committee chairman, to interrupt her and request that she be more respectful of the witness. A week later, she questioned Jeff Sessions, the attorney general, on the same topic. Sessions said her questioning "makes me nervous". Burr's singling out of Harris sparked suggestions in the news media that his behavior was sexist, with commentators arguing that Burr would not treat a male Senate colleague in a similar manner.

In December, Harris called for the resignation of Senator Al Franken, writing on Twitter, "Sexual harassment and misconduct should not be allowed by anyone and should not occur anywhere."

2018

In January, Harris was appointed to the Senate Judiciary Committee after Franken resigned. Later that month, she questioned Homeland Security Secretary Kirstjen Nielsen for favoring Norwegian immigrants over others and for claiming to be unaware that Norway is a predominantly white country.

Also in January, Harris and senators Heidi Heitkamp, Jon Tester, and Claire McCaskill co-sponsored the Border and Port Security Act, legislation to mandate that U.S. Customs and Border Protection "hire, train and assign at least 500 officers per year until the number of needed positions the model identifies is filled" and require the commissioner of Customs and Border Protection to determine potential equipment and infrastructure improvements for ports of entry.

In May, Harris heatedly questioned Nielsen about the Trump administration family separation policy, under which children were separated from their families when their parents were taken into custody for illegally entering the U.S. In June, after visiting one of the detention facilities near the border in San Diego, Harris became the first senator to demand Nielsen's resignation.

In the September and October Brett Kavanaugh Supreme Court confirmation hearings, Harris questioned Brett Kavanaugh about a meeting he may have had regarding the Mueller Investigation with a member of Kasowitz Benson Torres, the law firm founded by Donald Trump's personal attorney, Marc Kasowitz. Kavanaugh was unable to answer and repeatedly deflected. Harris also participated in questioning the FBI director's limited scope of the investigation of Kavanaugh regarding allegations of sexual assault. She voted against his confirmation.

Harris was a target of the October 2018 United States mail bombing attempts.

In December, the Senate passed the Justice for Victims of Lynching Act (S. 3178), sponsored by Harris. The bill, which died in the House, would have made lynching a federal hate crime.

2019

Harris supported busing for desegregation of public schools, saying, "the schools of America are as segregated, if not more segregated, today than when I was in elementary school." She viewed busing as an option to be considered by school districts, rather than the responsibility of the federal government.

Harris was an early co-sponsor of the Green New Deal, a plan to transition the country towards generating 100 percent renewable electricity by 2030.

In March 2019, after special counsel Robert Mueller submitted his report on Russian interference in the 2016 election, Harris called for U.S. attorney general William Barr to testify before Congress in the interests of transparency. Two days later, Barr released a four-page "summary" of the redacted Mueller Report, which was criticized as a deliberate mischaracterization of its conclusions. Later that month, Harris was one of 12 Democratic senators led by Mazie Hirono to sign a letter questioning Barr's decision to offer "his own conclusion that the President's conduct did not amount to obstruction of justice", and called for an investigation into whether Barr's summary of the Mueller report and his statements at a news conference were misleading.

In April 2019, Harris was one of 34 Senate Democrats and independents to write a letter urging President Trump not to cut aid to El Salvador, Guatemala, and Honduras. The group wrote:

On May 1, 2019, Barr testified before the Senate Judiciary Committee. During the hearing, he remained defiant about the misrepresentations in the four-page summary he had released ahead of the full report. When asked by Harris whether he had reviewed the underlying evidence before deciding not to charge Trump with obstruction of justice, Barr admitted that neither he, Rod Rosenstein, nor anyone in his office had reviewed the evidence supporting the report before making the charging decision. Harris later called for Barr to resign, accusing him of refusing to answer her questions because he could open himself up to perjury, and saying his responses disqualified him from serving as U.S. attorney general. Two days later, Harris demanded again that Department of Justice inspector general Michael E. Horowitz investigate whether Barr acceded to pressure from the White House to investigate Trump's political enemies.

On May 5, 2019, Harris said "voter suppression" prevented Democrats Stacey Abrams and Andrew Gillum from winning the 2018 gubernatorial elections in Georgia and Florida; Abrams lost by 55,000 votes and Gillum by 32,000. According to election law expert Richard L. Hasen, "I have seen no good evidence that the suppressive effects of strict voting and registration laws affected the outcome of the governor's races in Georgia and Florida."

In July, Harris teamed with Kirsten Gillibrand to urge the Trump administration to investigate the persecution of Uyghurs in China by the Chinese Communist Party; in this question she was joined by Senator Marco Rubio.

In July, Harris proposed a "Medicare for All" plan, stopping short of eliminating private insurance.

In November, Harris called for an investigation into the death of Roxsana Hernández, a transgender woman and immigrant who died in ICE custody.

In December, Harris led a group of Democratic senators and civil rights organizations in demanding the removal of White House senior adviser Stephen Miller after emails published by the Southern Poverty Law Center revealed frequent promotion of white nationalist literature to Breitbart website editors.

In 2019, GovTrack labelled Harris the "most liberal senator". In 2021, the label was retracted by GovTrack, citing "unreliablity" of their work, and re-designated Harris as the "leftmost Democratic senator".

2020

Before the opening of the impeachment trial of Donald Trump on January 16, 2020, Harris delivered remarks on the floor of the Senate, stating her views on the integrity of the American justice system and the principle that nobody, including an incumbent president, is above the law. She later asked Senate Judiciary chairman Lindsey Graham to halt all judicial nominations during the impeachment trial, to which Graham acquiesced. Harris voted to convict Trump on charges of abuse of power and obstruction of Congress.

Harris worked on bipartisan bills with Republican co-sponsors, including a bail reform bill with Rand Paul, an election security bill with James Lankford, and a workplace harassment bill with Lisa Murkowski.

2021