NEW YORK (Reuters Breakingviews) - Guns and social networks have several things in common. Many people enjoy them responsibly, but in the wrong hands they’re dangerous. Yet both enjoy an unfair subsidy in the form of legal protections that shield them from the actions of their users. That can’t last forever. Facebook founder Mark Zuckerberg and Twitter boss Jack Dorsey appeared before U.S. senators on Tuesday to justify censoring political speech. At issue is Section 230 of the Communications Decency Act, which broadly lets social networks off the hook for users’ posts, while also giving them the freedom to mark “objectionable” content. That law, which helped Facebook go from startup to $800 billion company, now effectively makes Zuckerberg and Dorsey arbiters of when content poses a danger to society. Gunsmiths too benefit from legislative Kevlar: the Protection of Lawful Commerce in Arms Act. It basically prevents gun violence victims from holding firearm-makers liable. But PLCAA means companies like Smith & Wesson and Remington can eschew simple, lifesaving features, such as indicators that show when a firearm is loaded. That omission costs lives. In 2020 there have been almost 250 unintentional shootings by American children, Everytown For Gun Safety says. Without these shields, both industries would change radically. Gun-rights supporters claim that without PLCAA, a sector with 47,000 workers would go bust. That’s probably hyperbole. But lawsuits and safety features would impose legal costs and make guns more expensive to produce. For social media, more active moderation would mean more employees. Users would have to get more used to the idea that their Facebook or Twitter posts aren’t free. Section 230 could change during President-elect Joe Biden’s administration, if Tuesday’s hearing is any guide. Not PLCAA. Even if Democrats wanted to repeal it, they’d need support from 60 of the 100 senators to even bring it to a vote. But the crony capitalism of PLCAA, and a shift among voters towards more firearm rules, suggests a reckoning will come. The incoming Senate, for example, includes firearm-safety proponents Mark Kelly of Arizona and John Hickenlooper of Colorado. Facebook and Twitter have an edge over gunsmiths. They know their legal impunity is threatened and are trying to get ahead of the problem. Dorsey and Zuckerberg have welcomed Section 230 changes. That’s sensible, because they can help reset the rules. Compared with gunmakers, they’ll then be better equipped to survive when their magical armor is taken away.