On a recent episode of “The Newsroom,” on HBO, the character Sloan Sabbith, a financial reporter, was mortified when an ex-boyfriend posted compromising pictures of her online, which then went viral. Her recourse – on the show at least – was to track down the offending creep and punch him.

If Ms. Sabbith were living in California, she would be closely following the deliberations of the state Legislature here this week. A proposal, to be debated Tuesday in the Assembly, could let victims of so-called revenge porn see their vindictive ex-lovers go to jail for up to a year.

The bill passed the state Senate earlier this summer. It would make it a criminal misdemeanor to post nude or revealing pictures that may have once been taken with a subject’s consent. The practice has become increasingly common, victims’ advocates say. And it poses a vexing legal question, pitting the rights of victims against the principles of free expression. Making matters more complicated is the fact that sites that host these user-generated images are usually immune from civil liability under federal law.

The California proposal is among a few state measures meant to designate revenge porn as a specific crime. New Jersey has one on the books. Florida floated a similar bill earlier this year, which free-speech advocates decried as overly broad. The California proposal, in its current form, differs in that it has been amended to specifically address people who distribute images “with the intent to cause serious emotional distress.”

The measure covers photos and video recordings of a person in “a state of full or partial undress in any area in which the person being photographed or recorded has a reasonable expectation of privacy.”

The question, though, is whether a new practice, enabled by the Internet, deserves a new law – or whether instead existing statutes provide enough protection.

“I’m unclear exactly how much ground the new law would cover that isn’t already covered by existing laws, such as anti-harassment/anti-stalking laws,” said Eric Goldman, a law professor at Santa Clara University, who has warned against newly criminalizing new online behaviors, “As usual, one of the key questions is how existing law has failed and what behavior is being newly criminalized.”

The American Civil Liberties Union opposed the measure when it was originally introduced and has said nothing about the latest amendments.

Its advocates argue that a specific statute is necessary because existing anti-stalking and harassment laws generally cover a repeated pattern of posting such images, and not one particular instance, which itself can be damaging. What’s more, they say, making the posting of these images a punishable offense under a new law would send a message to police and prosecutors. “It signals taking the issue seriously, that harms are serious enough to be criminalized,” said Danielle Citron, a law professor at the University of Maryland.

As for free expression, she argued that the law should distinguish between images that are meant to be public – protest art, for instance, which should get the highest First Amendment protection – and those that are meant to be private, like nude pictures.

Complicating matters, nonconsensual pornography, as the practice is sometimes called, doesn’t involve only a victim and a perpetrator. One person might record the image with the subject’s consent and post without consent, while another entity can host it – several Web sites specialize in doing just that – and many other Internet users can in turn spread that image far and wide in a matter of hours, or less.

“It’s not entirely clear what the culpability of each of these actors are in many contexts, or if they should equally be held liable,” said Woodrow Hartzog, a law professor at Samford University in Birmingham, Ala. He suggested using other laws, like breach of trust, to go after the individuals who post the material.

Web sites that host these images have a strong ally in Section 230 of the federal Communications Decency Act, which protects third-party platforms from liability for user-generated content. There have been efforts to weaken that immunity, most recently by a coalition of state prosecutors that urged Congress to amend the statute. They have been loudly criticized by some Internet free-speech advocates.