Trigger warning: People upset by accounts of extreme stupidity and politically craven spin may want to skip this column. Even people with a really even temperament may want to apply a layer of duct tape to their foreheads at once. That Planned Parenthood does not perform mammograms is indisputable. Its officials admit it; its president has even confessed as much before Congress under oath. But when a pro-life advocate says the same thing, PolitiFact, the self-appointed arbiter of truth and falsehood on the political scene, officially rated his comments "half-true." The controversy began when Casey Mattox, senior counsel with the...