Behe's argument of complexity has failed on so many levels it would require a book to list them all. The easiest way is to simply show that science has empirically disproved his claim that the bacterial flagellum is irreducibly complex. So as to be certain there is no mistake, here is how Behe defined his term of Irreducible Complexity: "An irreducibly complex structure is defined as . . . a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning." (Behe 1996a, 39)
Behe's assertion was that the bacterial flagellum was so complex that removing one single part would make it useless, and thus it could not have been produced over time by natural selection, which relies on useful mutations being passed on, as there would have been no benefit to the bacteria for having less than a total, working flagellum.
Unfortunately for Behe's claim, biologists have found a totally functional injector that some bacteria use to inject toxins into cells. It is called TTSS. It is now clear that a smaller subset of the full complement of proteins in the flagellum makes up the functional transmembrane portion of the TTSS.
In other words, the TTSS is a flagellum minus some parts.
And what was it again that Behe said about IC? "... wherein the removal of any one of the parts causes the system to effectively cease functioning."
Oops. So much for the Irreducible Complexity of Intelligent Design.