Bob Egelko for the SF Chronicle:

“By concocting this partisan redistricting scam, Gavin Newsom and Democrat politicians are openly violating the California Constitution and their oath of office,” DeMaio said in a news release. “Any vote … on this corrupt plan would be unlawful and unconstitutional.”

He argued that the state Constitution, under a ballot measure approved by the voters in 2008, allows only a bipartisan commission to draw district lines and does not permit them to be redrafted for political purposes.

The National Republican Congressional Committee also said Newsom’s plan would be challenged in court as well as the ballot box. Newsom “is shredding California’s Constitution and disenfranchising voters to prop up his Presidential ambitions,” Rep. Richard Hudson, R-N.C., chair of the committee, said on X.

But Rick Hasen, a professor of law and political science at UCLA who has written widely on election law issues, said the Legislature can ask California voters to change the state Constitution by placing an amendment on the ballot with two-thirds majority votes in each house. Newsom and legislative Democrats introduced their measure on Monday.

“If it’s a constitutional amendment approved by voters, then there is no state law problem with amending the earlier constitutional amendment,” Hasen said….

Another election law professor, Justin Levitt of Loyola Law School in Los Angeles, who was a national policy adviser for democracy and voting rights under President Joe Biden, said DeMaio was correct that the California Constitution currently prohibits legislators from redrawing district lines.

“But that’s exactly why the Legislature is proposing a constitutional amendment,” Levitt said. “And I’m not aware of any limitation on the Legislature to propose such an amendment for the voters to consider.”…

Hasen of UCLA said Newsom’s proposal might be challenged on other legal grounds, such as the rule limiting California ballot measures to a single subject. But he said opponents’ strongest argument would probably be a political one – that the voters should reject a plan to suspend the nonpartisan redistricting program they approved 17 years ago.

DeMaio appeared to agree on Monday. 

“If we stop it in court, fine,” he said at a press conference in the state Capitol. “But more than likely it will have to be stopped at the ballot box.”…