By Michael Duffy Opinions editor-at-large  Email Post columnist Ruth Marcus asked the central question of the week: “Why do we let children buy guns?” Ruth noted that the massacres in Buffalo and Uvalde, Tex., that killed 31 people were the work of two 18-year-olds, both of whom purchased their weapons legally. “They can’t purchase alcohol or cigarettes in this country until age 21. But deadly weapons? … If you’re 18 and want a semiautomatic assault rifle? No problem, except for a handful of states with stricter rules — and those are being challenged in court as unconstitutional.” Post columnist Michael Gerson, meanwhile, wrote that the so-called right of 18-year-olds to buy those weapons has lately come from “originalist” readings of the Constitution.  “What principle of constitutional self-government requires that the permissible age to purchase an AR-15 should be 18 rather than 21? A recent ruling out of the U.S. Court of Appeals for the 9th Circuit affirmed the rightof 18-year-olds to buy what most of us would call ‘assault weapons.’ Its reasoning? ‘America would not exist without the heroism of the young adults who fought and died in our revolutionary army.’ In fact, the enlistment age for the Continental Army was 16 — just 15 with parental consent. Some served at age 14. Is this a sufficient legal and historical basis to allow young teens to purchase nearly military-grade weapons in 2022? This type of 'originalism’ is indistinguishable from idiocy.” Let me know what you think. And thanks for reading.