Commentary We’ve all heard the joke: “How do you know when a politician is lying?” Answer:  His lips are moving. But there’s another obvious question that begs an obvious answer:  WHY do politicians lie? Answer:  Because they can. The American media–or what could once be legitimately called the media–draws our attention every day to the lies they have caught their least-favored politicians telling. Often, they are incredibly blatant. The furrowed brows on the left (CNN, MSNBC, and the major networks), were almost gleeful when they could trip up Trump in a self-serving fib. Carlson, Hannity, and other featured fellows on FOX News hold forth with a steady stream of reported fabrications and falsehoods, readily provided by a desperate president and his administration of race-baiters and pointy-headed socialists. Here’s the rub. Almost all the politicians’ lies, left and right, have been accurately (albeit selectively) identified by these outfits. We should be …