It's pretty much what Christians did. Jesus' (Yeshua ben Yoseph) matrilineal bloodlines don't trace to Moses or David, and that's what makes you Jewish, by birth. Moreover, IIRC, neither does Joseph's. And if we're tracing by Hashim, then logically, everyone does. So while Yeshua (Joshua) may be the Christians' Messiah, He isn't in any way, form, or fashion the one foretold by Jewish prophets.