It was derogartory only once in US history, during our civil war. The Rebels in the South called us that.
Today we call each other Yankees and Southern Rebels all the time in jokes. Hell, one of our baseball teams is called Yankees. Go ahead. Use it as often and as much as you like.
Back to the real issue here though. It seems Britain is definetly on our side, and may commit troops to any sort of war if one breaks out (thats iffy right now, with leanings towards there not being one...but...).
Its the rest of Europe that I am worried about. I hope that they don't forget us. The more people that show up for something like this, the better.
At least.....at least....help us with something else, like rebuilding the Trade Towers (controversial discussions, but we are having them).