It is among a wave of state-level activity aimed at regulating social networks on issues ranging from child safety to political bias, with some lawmakers and campaigners saying national efforts to limit Big Tech's power have stalled.
"My perception is that the federal government is paralysed," said Zack Stephenson, a Minnesota state representative promoting a bill that would prevent social media firms from using algorithms to decide what content to show to children.
"We have to start pulling levers ... It's not a silver bullet, but it's a start."
About 70% of the US population has a social media account, according to the Pew Research Center, while a 2022 study by the non-profit Common Sense Media found nearly 40% of children aged between 8 and 12 have used social networks.
There is rising debate over social media's influence, from data rights and free speech questions, to concerns over the mental health impacts on users and the spread of hate and misinformation online.
Carl Szabo, a vice president at tech industry group NetChoice, whose members include Facebook, TikTok, and Twitter, said tech firms are already responding, citing privacy features on Apple devices and parental controls in Google's Android operating system as examples.
National lawmakers have drafted a number of bills targeting the sector - from new privacy standards and algorithm regulations to stripping protections from liability over content posted by users - but none have yet been made law.
States are responding with a slew of action of their own, wading into heated debates over how much government should regulate speech and business.
There are currently more than 28 bills pending in over half a dozen states that aim to regulate social media platforms, according to research by the National Conference of State Legislatures provided to the Thomson Reuters Foundation.
In total, legislators in 34 states have considered over a hundred such bills, the data showed, though dozens failed to pass or did not progress to a vote.
"States are the laboratories of democracy," said Jesse Lehrich, co-founder of Accountable Tech, a non-profit group which campaigns for more regulation of tech platforms.
"Even more so when the federal government has failed to do anything on this issue for so long."
Szabo said such efforts to regulate social media risked infringing free speech and limiting consumer choice.
"We should allow individuals to make choices about what is best for themselves and their families," he said. "Not unelected bureaucrats and people sitting in state capitals."
CHILDREN, FREE SPEECH IN SPOTLIGHT
Among the most heavily contested issues is free speech, with Twitter and Facebook's bans of former President Donald Trump proving a flashpoint for debates.
Last month, the US Supreme Court temporarily blocked the implementation of a Texan law intended to prevent social media companies from banning or censoring users based on "viewpoint". A lower court blocked provisions of a similar law in Florida.
Industry groups say the moves to restrict platforms' editorial control would enable hate speech such as neo-Nazi abuse and foreign state propaganda, while some conservatives have complained that Big Tech is suppressing their voices.
Numerous other measures are aimed at protecting children. Many popular social media sites require users to confirm they are over 13 to sign up, but do not always demand proof of age.
In Minnesota, Democrat Stephenson worked with a Republican colleague to help win support for the bill aimed at preventing algorithms being used to choose content for children.
He said regulation was needed to prevent platforms designing algorithms that encourage compulsive use of social media and direct children to harmful content, such as responding to queries about dieting with posts that promote eating disorders.
The algorithm bill was killed in the state Senate, but Stephenson said he expects it to be re-introduced next session.
Szabo countered that such a ban would have broad consequences, such as blocking algorithmic recommendations from apps which suggest what books to read, or nearby hiking trails.
California's lower house passed a bill in May that would allow families to sue social media providers with over $100 million in revenue if they do not take steps to prevent under-18s from getting addicted to their platforms.
A second bill would impose design standards that include limiting the collection of location information and other sensitive data from children on platforms. Both bills require the support of the Senate upper house to become law.
"I want my kids to be tech savvy and tech native," said Buffy Wicks, an assembly member who authored the design bill.
"But I also want to make sure they're protected."
Some proposals to protect children online may actually lead to increased surveillance of users because it will put platforms under pressure to monitor underage activity, warned digital rights group the Electronic Frontier Foundation.
It could also result in censorship, the group warned, as platforms cleanse ever-larger amounts of content in order to avoid liabilities for harm.
Ari Cohn, a lawyer at TechFreedom, a tech policy nonprofit which generally opposes more regulation of the sector, said many state proposals undermined free speech principles.
"Social media companies have the right to decide what kind of speech they want on their platforms," he said.
Wicks said she hoped California's proposed regulations aimed at protecting children online will embolden other states to pass similar measures.
"We have a track record of pushing the envelope, and holding Big Tech accountable," she said.
Evan Greer, the director of the digital rights group Fight For the Future, said reining in the power of Big Tech long term will require more competition, handing consumers more options and limiting the power of individual platforms.
Greer backed efforts to target tech market giants with antitrust measures.
"We need to go beyond harm reduction ... and enact policies that pave the way for real alternatives," Greer said.
[Editing by Sonia Elks]