From what I understand, the US was contacted at some point in time. They saw how washington was setup and contacted us. The way they are mostly prepping us is through music, movies, and games. Why do you think Star trek was so advanced, and now we have a lot of those inventions? Look at our movies, for example Men In Black. For games, look at things like Starcraft. They have been trying to get us used to the idea, so when they come, we will for the most part be not afraid.
Look at George W Bush. He was OK when he was running the campaign, but if you look at him after he won, he was really fucked up. This was because he had seen the alien and their home world, it blew his mind, literally but he will eventually be OK.
New World Order? From what I understand, we were put here to evolve and create a master race of beings that would help the aliens. Think the British Colonies. Our world will be represented by the US mostly. America is the capitol of the world.
I'm really not sure who they contacted first. I don't really know when they came down. Something tells me it was fairly recently, when George W Bush was in power. But something also tells me we were actually left alone for a very long time (like God, and the bible). I'm thinking the "end of days" is actually when the aliens come. Unfortunately, we are pretty much a slave colony. Our world isn't the most brutal world to live on, but it's still very invasive. There are easy going worlds like Jamaica, or Amsterdam, but we AREN'T one of them.
They didn't attack us because they didn't need to. We were put here by them to evolve, and to see what would come out on top. We are a colony world, they use us for our resources and fighting power, and in return they help us out with technology. But, they will always be more advanced than us.