Sir Fragula said:
Wasn't Khan supposed to be ruler of Asia and China only?
According to Memory Alpha, Kahn was the first Augment to seize power, ruling 1/4 of the planet with a new united Asia/Middle East superpower that he built through peaceful means.
One year later, 40 countries were overthrown in one coordinated attack by 40 affiliated groups of Augments.
The Augments led their respective countries in wars against each other and/or were hit by mass revolt from the non-augmented Humans. 37 million people died. About a million per affected country.
Kahn was supposedly the greatest ruler of the Augments, since he didn't commit any war crimes nor try to conquer any other countries. This suggests that the other Augments did.
According to Voyager, America didn't give a crap because none of this was happening to them.
After the 40 groups were defeated, Humans decided that all Augments had dangerous levels of aggression and ambition as a by-product of their enhanced abilities (like Dr Bashir, right?), so they couldn't be allowed to live, so the world turned against Kahn, even though he wasn't really an asshole and was probably a better leader than anyone we've currently got in that region. But when they got to his door, they found he had retreated into space, so they covered it up and put up a "mission accomplished" banner.
30 years after Kahn left, a nuclear war was triggered (World War III). 600 million people died. Kahn might have prevented it.
Kahn was understandably pissed when he woke up and found his wife suddenly dead, so he picked a fight with Kirk, which is always a bad idea.
Edit:
Sir Fragula said:
You made me double-check, it's Khan dude! ;D
Facepalm. I suck.