SAN FRANCISCO >> California voters heading to the polls should leave their selfie sticks at home.

A federal judge on Wednesday refused to lift the state’s ban in the current election on sharing photos of marked ballots. U.S. District Court Judge William Alsup said changing the rules so late in the election process would create confusion.

“It’s not fair to the voters in California, the people who run those polling places and the secretary of state to jam this down their throats at the last minute,” Alsup said. The ban applies to photos taken in polling booths and at home or elsewhere by people voting by mail.

The ruling came on the same day a federal judge in Colorado heard arguments on that state’s ballot selfie ban. A legal challenge also is pending in New York.

There are laws against voters sharing any photo of their ballot in 18 states, while six others bar photography in polling places but allow photos of mail-in ballots, according to a review by The Associated Press.

Alsup said poll workers could be confused about whether people could use selfie sticks or take videos. He also raised concerns that photos that capture other people at the polling place might intimidate or disturb voters.

Ballot photo bans were enacted over 100 years ago as a way to prevent coercion, intimidation and vote buying, but they have raised First Amendment concerns in today’s era of social media and selfies.

The ACLU in a lawsuit filed on Monday said California’s ban violates voters’ right to freedom of speech by preventing them from expressing their political views. The group sought an injunction blocking the state from enforcing the ban in the Nov. 8 election.

Alsup said there were legitimate reasons to block people from sharing their marked ballots. He cited concerns about employers threatening to fire workers if they didn’t vote a particular way and demanding to see their ballots as proof.

Judges have struck down bans on the selfies in at least two states, and rules have changed in others. But in Colorado and many other states, sharing a picture of your ballot still carries potential fines or jail time.

California has not enforced its ban, and the state recently passed a law allowing photographs of ballots, including those taken at polling stations, to be shared, though that won’t take effect until January.

The ACLU said voters in the state needed clear guidance to prevent confusion that could have a “chilling effect” on their speech in the current election.

Michael Risher, an ACLU attorney, said after the hearing he did immediately know whether the ACLU would appeal.

In Colorado, U.S. District Judge Christine Arguello said Wednesday the way the law is written may pose valid constitutional problems over the right to free speech, but she did not immediately issue a ruling.

State Assistant Attorney General Matthew Grove said there appears to be no basis for a legal challenge of Colorado’s law. “We think that there is nothing to see here,” he said.

Colorado’s law was enacted more than a century ago to prevent vote-buying. State election officials say they don’t know of any cases where people have been charged with disseminating a completed ballot.

A Republican state senator, Owen Hill, said Colorado’s law should be struck down if no one is being prosecuted for taking pictures with their ballots.

But Colorado Secretary of State Wayne Williams said the ban is important and ballot privacy should be maintained.

It’s not clear if Arguello will rule before next week’s election.