Is Jesus God or is he the son of God?
A fundamental question which Christians still can't agree on after nearly 2000 years.
First place to start is with Jesus' claims; then how God the Father refers to him at his baptism, and then how the early church understood the situation. Church tradition, alone, isn't valid; realistically, one of these 3 elements alone isn't sufficient evidence, but when all 3 come together as they do in the NewTestament, it is pretty decisive.
As for your second point, it is one of the 2 or 3 fundamental points that the vast majority of Christians (and probably all mainstream Christians) agree on.
Furthermore, there have been attempts over that same 2000 year period to knock the idea over, all of which have proved fruitless.