[steve-b]

That is the logical fallacy of the false dilemma, although three-way instead of the usual two-way. A fourth possibility is that Jesus is misrepresented by those writing about him.

A fifth is that, given the circumstances (the relatively recent destruction of the Maccabean kingdom and Roman conquest), for a Jew who believed that his religious scriptures actually meant what they said to expect the imminent arrival of a Messiah was not "lunatic" at all -- and if the Messiah is coming, why should it not be one's self, if the signs seem to point to that?

[WriteOn]

That's actually so close to the truth as to be a devilish trick. :-)