California Gov. Gavin Newsom signed a bill Monday that requires vote-by-mail ballots to be sent to all registered state voters in every election.

The bill, AB 37, was authored by Assemblymember Marc Berman to boost voter turnout and strengthen election integrity, according to a press release from Berman’s office. This makes California the sixth state to require registered voters to receive vote-by-mail ballots before each election, alongside Oregon, Hawaii, Utah, Washington and Colorado, the press release said.

California began sending vote-by-mail ballots to every registered voter during 2020 due to the COVID-19 pandemic, which led to “record voter participation,” according to a press release from Newsom’s office.

“Mail-in-ballots opens the door for voting to be more accessible and easier,” said ASUC Vote Coalition Director Junshik Ham in an email. “Voting is an edifying foundation for our democracy, and it is important to encourage participation through promoting different means to vote.”

Charlotte Hill, a postdoctoral researcher at the UC Berkeley Goldman School of Public Policy, said she has done research on Colorado’s vote-by-mail system and found it significantly impacted voter turnout, especially for groups such as young voters and voters of color.

While it is not guaranteed that California’s vote-by-mail system will achieve those same results, Hill noted that it is likely that California will also see increased voter participation from certain demographics.

“Our research suggests that mail voting has the power to dramatically boost voter turnout, especially among groups that historically have faced greater barriers to voting,” Hill said in an email. “It can be easy to think that the voting process is simple and straightforward for everyone, but the reality is quite different.”

According to an Assembly Floor Analysis of AB 37, opponents of the bill argue that legislators should not consider expanding voter access in this manner.

The Election Integrity Project California alleged in the analysis that allowing voters to mail their ballot up to seven days after Election Day would give individuals time to tamper with election results, and sending vote-by-mail ballots to every voter opens up the possibility of sending ballots to those “no longer in a position to vote legitimately.”

“All voters deserve protection from the potential cancellation of their legal ballots by those who are facilitated to double vote, vote from the grave, vote from another state, etc.,” the Election Integrity Project California says in the analysis.

Claims of voter fraud from vote-by-mail ballots have been raised and amplified during previous presidential elections, particularly in 2016 and 2020, according to some UC Berkeley professors.

However, Hill said research has repeatedly shown that voting by mail is “safe and secure.”

“Voter fraud is virtually nonexistent in America, and claims that vote-by-mail will somehow lead to fraud are disingenuous and destructive to our democracy,” Hill said in an email.