I am not fully informed on the common core but have heard lots of discussion against it from friends.  If indeed, it changes historical facts about our nation it is concerning.  I think that those who know of it say that it does not allow for patriotism to be taught, it teaches different people as American founders than those that are traditional and that it seems to dumb down the curriculum.  Because of the negative information I have heard from individuals, I have formed a negative opinion from the start.