What would happen to Iran if an invasion is to happen?

Ok guys.I don't want any theory from any particular persons such as Robin Wright or John Titor.I want predictions on what might have happen if Iran is invaded by the U.S and her companies according to what you think and feel.

In relations with the Iran-U.S tension,Iran herself has political issues and struggles in their own Islamic government.With the barring of thousands of reformist candidates by an unelected right-wing body from competing in Iran's general elections,the future for the Islamic Republic is seriously unknown.Could the U.S invasion bring about the reform they need besides the halting of their nuclear ambition?

My curiosity:
1)Will U.S bring about democracy as they did in Iraq besides searching for WMDs if they were to invade?

2)What will happen if Iran were to be invaded?

My predictions:
It is evident in history that U.S is known for bringing about democracy and freedom to nations that are oppressed(e.g Afghanistan,Iraq etc.).Moreover,Iran being an Islamic Republic,I think Bush will somehow figure out some reason to take them down and introduce democracy.Even in the case of N.Korea as they are still a Communist country,Bush might want to "liberate" them behind the reason of the nuclear armed threat.