Iranians are Persians, not Arabs (Arabs speak Arabic, Persians speak Farsi) - this is important to note because the Arab world is somewhat disconnected from Iran, though there is a large overlap in population considering Iran to be a Muslim nation.
The Iranian government will use this as an opportunity to take strong action against any public opponents and individuals they consider to be threats to their security due to any significant political dissent. They will arbitrarily use force against citizens to maintain fear of resistance to the government, and they will claim some public triumphs over dissenters. This all means that they will pretty much keep doing what they do, but step it up a bit in response to this.
The important observation internationally should be in how the rest of the Muslim world (and the Arabic world) respond to this - Obama is strengthening relations with the Middle East by taking steps towards ending blind US support of Israel (and their state-sponsored terrorism) and as a result, Arabic nations are warming up to the US considerably, especially because they are no longer arbitrarily denounced in the "Israel vs everyone else" issue over there. Iran is not Arabic, but the Islamic ties of unity are still strong, and while Iran has been militant and rogue in its opposition of Israel and US support of Israel, the public/international face of Iran is clearly on his way out and trying to stay in by force. Ahmedinejad is trying to stay in power through the arbitrary exercise of said power, but several other authorities are well-seated and they aren't going anywhere regardless of what happens to him. The media does little to show the power of Ayatollah Khamenei, the Council of Elders, and the Assembly of Experts - they have much more authority over what happens in Iran than the President.
This chart explains it to a limited extent, but it does not reflect the significance and power of the Ayatollah, the Council of Elders, and the Assembly of Experts.
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