Who would come to aid the USA?

There are so many disasters in the world. The Tsunami, the Earthquake in China, the current conditions in Myramar.

There are countries and volunteers lined up to go in and help, even when that help is turned away. The USA drops food, send people to help, and is always there.

Now some people may think we are poking our nose in other's business, but I think that people truly want to help.

My question is, what would happen if something that devastating, that horrific happened here in the USA? Would anyone come to help us? Or would people think we get our due because we parade our wealth and power around the world.

We have had these events, Hurricane Katrina and the attack on 9/11. I don't remember much help from other places. Maybe I just didn't hear about it... but it makes me wonder.

Who would help us if our country and way of life was about to fall apart? Maybe that is why people are so paranoid and that is why there is so much fear in our country. This is starting to frustrate me.