Answer
Mahmoud Ahmadinejad was the incumbent president of Iran, and he ran for re-election in the 2009 election. He was challenged by Mir Hossein Mousavi, who was the prime minister of Iran from 1981 to 1989. The election was widely criticized as being rigged, and Mousavi's supporters held protests in the streets of Tehran. Ahmadinejad was declared the winner, but the protests continued for weeks.