> A political essay is (typically) written by certain persons to > persuade the public of a certain position. If it is modified, > it does not do its job. So it makes sense, socially, to say > that these cannot be modified. Then, why are there so many political essays under the GFDL, without invariant sections? You'd have to ask their authors about that. I won't criticize their decisions, but I don't see a reason to do it.