Will we ever be able to colonize planets outside our own solar system? We're discovering more candidates all the time, as the article cited below reveals. But, they are so far away that many of them would require trips much longeer than the time from the original colonization of this country to now. We only have a dim awareness of our ancestors who took that journey. They all have one thing in common -- they're now dead!
Unless we can find some way of exceeding the speed of light, it looks virtually impossible to even contemplate anyone setting out on such a journey and living to see the end of it. Whole generations of humans would have to survive on a vehicle containing complete eco systems without ever breaking down in transit, evading all the hazards of interstellar hostile environments, etc.
Interstellor space is mostly empty, but not totally so. A host of wandering objects have to be out there and a hurtling spacecraft could easily wind up hitting one. Once in awhile, wandering objects like that have hit spaceship earth, and the dinosaurs didn't fare very well in the last big collision. There's even reason to believe another pretty big one led to the demise of the mammoths and other ancient fauna and a considerable number of humans as well.
For the immediate future, I think we'd better concentrate on maintaining the habitability or our own fagile world and quit acting like we have somewhere else to which we can move. Instead of worrying about maintaining hegemonic supremacy over other nations, we'd better start concentrating on cooperaating to ward off disasters that could very easily be heading our way from way out there and on keeping this fragile old planet hospitable.
Here's the article that set off this train of thought: