I guess I'm with theory number 4: IOW theory 3 is correct except that it is a setup, so that they can jam a liberal down our throats anyway, claiming that it's our fault the conservative nomination failed because we don't have 60 conservative votes in the Senate. According to that theory, that's why we got a white male Alito instead of a black female JRB.
We don't want to put those poor McLame RINOs and Democrat "moderates" in a really hard spot, now do we?