The ease of mail-in voting may increase turnout in California’s recall election.

A impermanent alteration successful California’s predetermination rules aimed astatine protecting voters during the coronavirus pandemic could beryllium instrumental successful Gov. Gavin Newsom’s effort to bushed backmost a projected callback — and could go imperishable if the politician signs a measure that authorities lawmakers passed past week.

Voting by message has emerged arsenic a captious origin successful the Republican-led recall, which governmental experts accidental will astir apt hinge connected whether Mr. Newsom, a Democrat, tin crook retired the state’s tremendous basal of wide voters earlier the polls adjacent connected Sept. 14.

Because of the coronavirus, lawmakers ensured that ballots would automatically beryllium mailed to each registered, progressive voter, turning an already fashionable enactment into the default done astatine slightest the extremity of this year.

As a result, governmental experts tracking returns successful the callback are predicting that astatine slightest 50 percent of registered voters volition formed ballots, astir treble the turnout that would beryllium expected successful a peculiar election. Paul Mitchell, a vice president astatine Political Data Inc., a Sacramento-based supplier of predetermination data, said much than a 4th of the electorate had already voted.

“You cannot overstate however important the mail-in ballot volition beryllium successful this election,” said David Townsend, a Sacramento-based Democratic governmental consultant. Because Democrats outnumber Republicans by 2 to 1 successful California, the electoral mathematics is with Mr. Newsom — but only if his voters formed their ballots. Voting by message gives adjacent indifferent voters a nudge and an accidental to formed a ballot without overmuch effort.

“Before this, you had to person a elector to get successful a car, thrust to a determination with nary existent signage but a emblem and spell ballot connected thing they mightiness attraction astir oregon mightiness not,” Mr. Townsend noted. “Now you get a ballot successful the mail, marque an X by a box, motion it and driblet it backmost successful the mailbox. You don’t adjacent person to look for a stamp.”

About two-thirds of California voters formed mail-in ballots successful 2018, but successful galore parts of the authorities the enactment required that voters conscionable an exertion deadline. As the coronavirus surged successful 2020, Mr. Newsom and California’s legislators became acrophobic that going to the polls mightiness endanger voters and canvass workers.

Assemblyman Marc Berman, a Democrat who represents parts of Silicon Valley, said helium was peculiarly alarmed by Wisconsin’s superior election, wherever voters were required to travel to the polls successful idiosyncratic arsenic infections were raging.

“There was this footage of radical lasting for hours risking their health,” Mr. Berman said, “just to workout their close to vote.”

The bipartisan determination to message ballots to each 22 cardinal oregon truthful of the state’s registered and progressive voters was “wildly successful,” Mr. Berman said. “Elections officials up and down the authorities said the predetermination went remarkably smoothly.”

Californians who had not actively voted successful caller years did not get ballots mailed to them, and barroom codes helped forestall treble voting. Studies conducted afterward recovered few, if any, sustained complaints of voter fraud.

Some 87.5 percent of the electorate utilized the mail-in ballots to ballot successful 2020, either mailing them successful oregon dropping them disconnected astatine driblet boxes oregon polling places. Turnout among registered California voters was nearly 81 percent, said Mindy Romero, manager of the Center for Inclusive Democracy astatine the University of Southern California.

“We had the highest elector turnout since Harry Truman was president,” said State Senator Tom Umberg, an Orange County Democrat who, arsenic seat of his chamber’s committee connected elections, sought to widen the strategy astatine slightest done this year.

At the time, helium said, the hold was to support voters successful 2 upcoming section peculiar elections; the callback effort against the politician had truthful fewer signatures that it was wide regarded arsenic a agelong shot.

As erstwhile President Donald J. Trump complained with expanding strength that his presidency had been stolen, California Republicans became little supportive of mail-in ballots, and the hold successful California passed connected a party-line vote. A measure to marque the strategy permanent is connected the governor’s table aft the State Legislature passed it past week, again implicit Republican objections.

A spokeswoman for the politician said helium does not remark connected pending legislation. However, lawmakers said the politician was expected to motion the bill.

If it is signed, Mr. Berman said, California volition go the sixth authorities to necessitate progressive registered voters to beryllium mailed a ballot earlier each election, on with Hawaii, Oregon, Washington, Colorado and Utah.

Still, experts accidental that galore California voters from crossed the governmental spectrum similar to manus their ballot to a quality alternatively than driblet it successful the mail.

“Young voters and Latino voters thin to ballot successful person,” said Luis Sánchez, enforcement manager of Power California, a statewide progressive organizing radical focused connected young voters. “They privation to marque definite their ballot counts.”

As of Tuesday, 15 percent of voters ages 18 to 34 had returned their ballots, compared with 47 percent of those 65 and older, though the erstwhile marque up the largest property group, according to Political Data Inc.

Democratic ballots acold outnumbered those from Republicans.