“No True Scotsman,” in addition to being the name of this blog, refers to a particular logical fallacy. Discussed in greater detail here, here, here, and here, the fallacy consists of redefining a class in such a way as to confirm a thesis. So, for example:
Alfred: No Michigander puts ketchup on a coney.
Wayne: I’m from Ypsilanti, and I put ketchup on coneys.
Alfred: No true Michigander puts ketchup on a coney.
This is a technique used with some frequency by political activists (from a lot of different orientations). But it’s a circular argument, and should be pointed out and possibly ridiculed.