Andrea Widburg: Marjorie Taylor Greene won the GOP nomination for a Georgia seat in the House of Representatives. Politico paints this as a GOP disaster because it claims that Greene says racist, Islamophobic, and anti-Semitic things. House Republicans, who have learned nothing from Donald Trump about fighting back against media calumnies, dutifully piled on. In fact, Politico is defaming Greene, who is not racist, is not anti-Semitic, and is not unreasonably concerned about sharia Islam in American politics. Tuesday's Politico article is entitled " New GOP headache as candidate condemned for racist videos wins Republican primary ." It relies on an earlier Politico article that purports to have discovered that Greene made "incendiary" comments against Muslims, Jews, and blacks. In the earlier article, entitled " House Republican leaders condemn GOP candidate who made racist videos ," Politico...