The other day I was standing in the gift shop at the National Museum of American History staring at the display of donkey- and elephant-branded merchandise when a stocky white guy in his mid-thirties came over and grabbed an armful of red GOP t-shirts and a large metal “Republican and Proud” plaque. “Can’t resist,” he said to me. I suppose he thought I would be sympathetic because I was wearing a t-shirt that said “Sports!” in that curly American writing that Coca-Cola has probably trademarked. “I work in healthcare,” he told me, after I nodded and grinned mutely like the weak-kneed liberal I am at heart. “Everyone around me is a Democrat. And I own my own business, so…” So, …