Do you think the discovery of another intellegent race/species would unite the world, or further divide it?

People fight, just look at families; brothers and sisters always fight, but if anyone else hurts them they stand up for each other. And this idea goes on up, the school rivalries, even to a national level. People stand together against an outside threat, I see no reason the world wouldn't unite against a new intelligent species, if they were aggressive or peaceful, humanity would still unite in an us and them mentality for the most part.