We've lost William F. Buckley, (arguably) the most important conservative of the 20th century. In the coming days, many will try to summarize the effect he's had, but it will be almost impossible to do. I do not think it is far-fetched to say that without Buckley, there's no Reagan. In fact, without Buckley, there's probably no modern conservative movement.
This is most unexpected and saddening, indeed. He's been writing right up until the present.