Nashwan your reasoning is faulty. The US went into Iraq and destroyed it's once formidable army with little effort. We then went back and overthrew their government with little effort. What we can't do and probably never will be able to do is establish a democracy there if the people don't want it. Overthrowing governments though, no problem.
If the US attacked Iran, you could do a lot of damage to them. But when you finish attacking them, the end result is their government gets back in power. In fact, it's likely to be a more hardline government.
It's like Gulf War I. The Iraqi army was smashed, but Saddam remained in power. You can smash the Iranian army, but the only way to change their government is to invade in large numbers, and you have to stick around long enough to establish a different government. Otherwise, all you achieve is damage to Iran, at the cost of damage to the west with substantially higher oil prices.
Do you think an invasion and occupation of Iran is on the cards now?
The Iranian government is no longer worried because they know the west can't hurt them badly. We can bomb some of their installations, but anything beyond that is out of the question at the moment, and for the next few years.
We shot our bolt in Iraq.
