We know he lies and that he is a Commie sympathizer.
We know he hates the “west” because of granpappy being jailed in Kenya
WE know he still hasnt selected a church.
We know he is wrecking the economy and winking to our foes.
To publicly reveal that Obama didn’t write his own book—and that a terrorist to whom Obama denies close association did write it—is more concrete (and it proves Obama to be a liar, a thief and probably worse) than anything from your list, and as such it can potentially sink Obama much faster than anything else we have on him.
As such, expect Obama’s closest fellow schemers to put out a very intense effort to stop this in its tracks.