On the left manifest destiny is manifestly taken as a system of white, male colonization.
I agree, in that it was useful as an organizing principle of the colonization of the North American continent. *However* I know that it was also a useful organizing principle (something our society lacks today), and that for many oppressed European peoples, being given free land and a chance in north america made their lives much better. The need for some sort of societal direction, some sort of agreement other than "shareholder value" that has some sort of ethical component. The ideal of manifest destiny was closely tied to christian "virtues" of settling the land and extracting value from it. While I think we can see that short sighted short term thinking leads to pollution and destruction of the land, we as a country need some sort of organizing principle that at least the majority of the nation can solidly, and through the generations, get behind. Personally I think  it was the ideal of manifest destiny that brought us to the high frontier and allowed the USA to accomplish one of its signature feats: put a man on the moon. the USA was founded as an expansionist settler state. We need to imagine we are expanding our little "cities on a hill." Lets take our military industrial complex and put it to better use: expanding our manifest destiny to the stars. Yes I am a trekkie. I think most peeps on the left want to try and fix our problems at home, and could give a damn about the space program.