I think one nice quality of persuasive people is that they spare me from having to think. For instance, anyone who moves to California must suddenly contend with a tyranny of ballot initiatives. Only thanks to Kevin do I have an inkling of how to respond to them. (The short answer is No, although restrictions apply. Consult Kevin's archives for details.) He's a master of making an argument succinctly and persuasively, and he doesn't show off. You just know he's done the work.
Blogging is a medium that encourages a what-am-I-thinking-right-now style, and Kevin is of course great at that sort of posting. But when it comes to what to make of big questions of the moment--the surge, oil production, the economy--Kevin is also that rare commentator who pores studiously through articles and books before coming to a considered yet concisely rendered opinion. Sure, he's unusually wise and decent, but he also just does the work. It's enough to make the rest of us think we should do the work, too. Come to think of it, thank God he's leaving.