Presenting Mormon tritheism:

Just to clarify, Mormons in fact do believe that Christ is God. It’s really quite simple. There is one God, which is the Godhead, consisting of three separate beings [bold mine-DL] in the way that the Bush Administration is one administration consisting of many people. God the Father, Jesus Christ who is also God, and the Holy Ghost, who is also God. They are one in purpose. It’s not more complicated than that. Mormons do not believe in the Nicean [sic] Creed, but Christ’s role is not undermined.

In other words, Mormons do not share the fundamental doctrine of God that all Christians share and quite explicitly accept something that undermines monotheism.