Love love this. I don't know what it's actually about. My mother is native Canadian Indian and that's all I think about is taking land and homes from them with disregard... Love for me me every time I hear it!!!
It's about the Europeans colonizing (the) America(s) and oppressing the natives. "Away away, you have been banished / your land is gone and given to me". About how entire cultures have been exterminated to make way for the "civilized" "Western" way of life and forcing everyone else to adapt to this way of life abandon their traditions and values. And the "don't drink the water / there's blood in the water" part, I think, refers to the fact that what Americans take for granted nowadays is built upon centuries of bloodshed, so the water is tainted by the wrongdoings of the past. (e.g. in the Live Trax, Vol. 11 performance of this song, he sings "don't drink the water / there's blood in the water / this American water") If you can find it somewhere online, there's a recording of VH1 Storytellers where Dave talks about the song.
