Originally Posted by Romanus

I think we'd already have independent off-world colonies...but with complications.

As RB said, there would definitely be an issue of contamination, both forward and back. There would be *lots* of environmental questions. Last, but certainly not least, would be issues of sovereignty. An Earthlike planet next door, especially one rich in in-situ resources, wouldn't be like Antarctica IMO, in which countries don't really care whose sector is where. I think a "scramble for Africa" repeat wouldn't be out of the question, to say nothing of any possible move of actual independence on the part of the colonists.

Interesting times, indeed.