6 Years Ago, Democrats Failed on Guns. Have They Learned From Their Mistakes?

Beto O’Rourke reshaped the national gun debate when, in response to a string of deadly mass shootings, he called for a mandatory buyback of the military-style assault weapons used in the massacres. “Hell yes, we’re going to take your AR-15, your AK-47,” he said during last week’s debate. “We’re not going to allow it to be used against our fellow Americans anymore.”

Gun rights advocates were enraged; one right-wing Texas lawmaker responded with what appeared to be a death threat. Even some Democrats—who for years had assured voters that no...