In that event, Democratic Gov. Gavin Newsom would appoint a replacement who would serve out the remainder of Harris' term, which would end in 2022. There are currently a number of prominent California officials who could be tapped for the job.
“There are so many factors that go into a decision like this for Newsom. Fundamentally, it’s about his legacy,” Democratic strategist Rose Kapolczynski told the Los Angeles Times. “At this moment in time, there is going to be a lot of pressure to appoint a person of color. The dynamics may be somewhat different in November and December, but I don’t think this national reckoning on racial justice is going away.”
If Newsom is looking at race as a factor, there are a number of minority figures to choose from.
Rep. Karen Bass, chair of the Congressional Black Caucus, was -- like Harris -- on Biden's shortlist of potential running mates, and she has made a national name for herself during a period of racial tension in the U.S.
Bass has been a staunch supporter for criminal justice reform, while opposing the idea of eliminating police funding. While she has supported the idea of reducing police budgets in favor of other programs, she called out the "defund the police" movement for using "probably one of the worst slogans ever."
Secretary of State Alex Padilla has been seen as a potential future senator as well. A former staffer for long-time Sen. Dianne Feinstein, Padilla has been considered as a possible Feinstein successor in the past, according to the Times.
Padilla also has strong ties to Newsom, having chaired the governor's failed 2010 gubernatorial campaign.
State Attorney General Xavier Becerra is also a possibility. Becerra has used his office to challenge President Trump through lawsuits dealing with a number of sensitive issues including DACA, a citizenship question on the Census, auto emission standards, and climate change.
To date, Becerra has spent $43 million in taxpayer dollars while suing the president, according to the Sacramento Bee.
Controller Betty Yee and Treasurer Fiona Ma are among other state officials whose names have popped up as possible contenders.
Should Newsom decide to choose someone with a history of challenging the Trump administration in Washington, he could look to the House and choose either Rep. Katie Porter or Rep. Adam Schiff.
Porter drew notoriety when, during a tense round of questioning, got Centers for Disease Control and Prevention chief Dr. Robert Redfield to commit to providing free coronavirus testing.
Schiff, meanwhile, has been among the most well-known members of the House in recent years. As chairman of the House Intelligence Committee, he led the impeachment inquiry of President Trump and was among the impeachment managers at Trump's Senate trial.
According to a spokesman for Newsom, the governor is not concerning himself with replacing Harris just yet, as he is concentrating his efforts on the coronavirus pandemic.
“It’s the furthest thing from his mind,” spokesman Nathan Click told the Times. “The governor is squarely focused on leading the state’s response to COVID-19 and helping Californians during this global pandemic.”