“We must finally hold social media companies accountable for the experiment they are running on our children for profit.And it’s time to pass bipartisan legislation to stop Big Tech from collecting personal data on kids and teenagers online, ban targeted advertising to children, and impose stricter limits on the personal data these companies collect on all of us.”

President Joe Biden got a standing ovation from Democrats and Republicans when he proposed tough regulation of social media in February’s State of the Union address. But getting something into federal law is proving tricky.

The US has lagged the UK and the EU on online regulation. Europe’s General Data Protection Regulation has become a global template for privacy and has for now been retained in British law.

Until more recently, the UK had been considered ahead of the game in moving to the next stage, combatting harmful content, with its proposed Online Safety Bill. Currently in the House of...