Mahmoud Ahmadinejad
His 2009 landslide re-election to a second term — with more than 60% of the vote — caused an uprising in Iran. Mahmoud Ahmadinejad's main opponent, Mir-Hossein Mousavi, and his supporters cried foul, demanding a recount and later calling for the results to be thrown out. Dozens of people were killed in demonstrations that were quelled by paramilitary forces. After a week of intense protests, Iran's Supreme Leader Ayatullah Ali Khamenei declared the results to be valid and affirmed Ahmadinejad's victory. Just a few days later, the country's Council of Guardians confirmed that 50 constituencies had returned more votes than there were registered voters. Ahmadinejad and Khamenei clashed on several political fronts, including who would be part of the President's Cabinet. That tension, coupled with a lingering, broad-based opposition to Ahmadinejad's administration — including among some of the country's clerical elite — has kept Ahmadinejad, who wields his power with the backing of the mullahs, on shaky ground.