> Point is that if we can not behave on Earth how can we do it in other place.

If we have a 90% chance of behaving in any given century, we are doomed on earth. If we have a 10% chance of behaving in any given century, a continuous heritage is possible in a galaxy (re-)populated by slowships.

it's an open question as to how interplanetary politics will actually go. it's possible that ancient squabbles between countries will carryover, but hopefully they won't, which means that a terrorist's nuclear bomb causing MAD on Earth wouldn't necessarily carryover to MAD on a terraformed Mars and Lunar colonies, as we saw with the Russians who boarded the ISS in blue and yellow. But even if it doesn't, Earth being hit by an asteroid is another scenario that being a multi-planetary species would prevent our extinction in.