As I walked down the street near my home in suburban Virginia recently, I saw a decrepit Volvo sporting a bumper-sticker palimpsest. The barely legible original layer must have been as ancient as the vehicle itself, and by now there was no bumper space left, fore or aft, uncovered by this automotive wallpaper. What could be read of it consisted of the names of mostly forgotten Democratic candidates, national, state, and local, from the last twenty years or so and fragments of slogans that had once cost several Volvos’ worth of focus groups to come up with. That’s really the problem with bumper stickers, isn’t it? However great your enthusiasm for a candidate or his pithy surrogate wisdom, people probably don’t want to be reminded of it twenty years later. For most of us, the urge to identify ourselves with a particular candidate seldom survives more than a year or two in office unless we are the kind of party hack for whom an unb ...