The Department of Homeland Security has proposed a rule that should have sent shockwaves through every newsroom in the country: visitors entering the United States under visa-waiver programs may soon be required to hand over five years of their social-media history before boarding a plane. No context, no criminal suspicion, no triggering event, just a mandatory reveal of your digital life, tied directly to your passport.On paper, the justification looks familiar. DHS presents the change as a security upgrade, a harmless modernization of screening tools to help identify threats. They repeat the same vocabulary Americans have been conditioned to accept...