I am gonna to quibble here. One does not have to have the ability to terraform Mars to place a sustainable colony on Mars. It is just that a sustainable colony on Mars is so similar to a sustainable colony in space that I really do not see why we would put it on Mars initially as distinct to somewhere more accessible.There just isn't any reason to go. Despite sci-fi dreams, terraforming is essentially impossible (or, at least, if you can terraform Mars, you can terraform Earth to fix whatever issues we have caused). yes, it would be a good idea to be a multi planet species, but if a colony is not sustainable (and Mars could never be) then if Earth life gets wiped out, so does Mars'.
To be honest we have in my opinion the ability to fix the issues we are causing here on Earth but not the collective political will to actually do it.