To understand an Iranian president, you have to remember that even though Iran is called an Islamic Republic, the system of governance is more like a monarchy. The president of Iran is effectively the prime minister of an absolute monarch. Iran’s supreme leader-formerly Ayatollah Khomeini, currently Ayatollah Khamenei-is the man who really rules Iran. The Leader must formally accept the people’s choice for president, and if push comes to shove he can order the president’s resignation (Khomeini did just that to the first president of Iran, Abol Hassan Bani Sadr, in 1981.) So even though people can elect their president, a successful candidate must have the tacit support of the Supreme Leader. According to people close to the Leader, Ahmadinejad still enjoys his support. Khamenei seems to enjoy Ahmadinejad’s aggressive rhetoric and agrees with most of the president’s policies, and doesn’t mind if they continue for four more years.
Read the whole thing, but the key is to realize that Iran’s radicals aren’t going anywhere, and they won’t abandon their nuclear ambitions no matter how much Obama wishes they would.