We shalt Colonize Mars with Our Mighty Technolo...
Oh, wait, am I now starting on this again... *Sigh*
It isn't a question of technology knowledge or availability. The problem is money: why the US or whatever government should spend billions to colonize Mars? Which are the advantages?
The first landing on the Moon brought a lot of prestige to the United States because they won the race with the URSS, but now?
Resources? They can't be extracted and brought to Earth cheaply from Mars.
Life? Probes can do it without humans. (Spirit, Opportunity...). And however, after discovering life on other planets, there aren't concrete advantages...
Prestige? Maybe, but not like the landing on the Moon. Why? We already know we can do it...
A more useful colonization would be the Moon one: the Moon can be used as a very efficient vacuum factory and as a launch pad at 0.15 Earth gravity. And it is nearer, so cheaper.