Backers of Democratic presidential hopeful Bernie Sanders are filing an emergency federal injunction, demanding all so-called unaffiliated voters who already voted be allowed to re-vote if they want to.
San Francisco's city attorney said he was warned by Sanders backers of the injunction, which is expected to be filed Friday and comes just weeks before California's primary election on June 7.
The injunction seeks to force counties across the state to allow voter registration up until Election Day -- a move opponents said would create chaos in the state primary process.
"It does because it means the information you have at the polling place as to who is actually supposed to be there does come into play," said Virginia Bloom, Santa Clara County's Assistant Registrar of Voters.
The injunction could also mean ballot shortages at some polling places.
Sanders supporters said the change may be painful, but is necessary.
"I know there have been some voter issues and misinformation, so it gives more people time to get involved," voter Hilda Arakelian said.
The Secretary of State's Office in Sacramento is keeping a close eye on the legal challenge.