The Iraq war was misbegotten from the beginning. The justification (that they were working on nuclear weapons) was a lie told to the American people, and everybody else.
There were multiple reasons given, not just one. It was better for the US to focus on that one thing so as to not spook allied dictators.
Worse, the US did not display insight into how to remove a mostly hated dictator without collapsing the whole society into chaos from which they have still not recovered. It was an altogether inhumane AND incompetent operation.
No, this is being wise after the fact. If the US had done it any differently, and it had failed, you would instead be on here saying it was "obvious" that democracy wouldn't work with the approach taken. The societal collapse was a facet of Iraqi culture in the absence of an oppressive force. With the information available at the time, it was necessary to remove that oppressive force so that the Iraqis would genuinely believe that they were free. As a result, 300+ political parties started up, and there were long lines to join the new Iraqi security forces, despite the fact that the country was still under US occupation. It could have been very different if neither of those things had happened, and democracy failed.
The Iranian people will have to work out their own liberation -- not because nobody cares about them, but because it seems highly unlikely that the US, or any other power, can confer liberation upon them.
This is actually part of the reason why it's so important to go into Iran. Until we actually get in there and do it, you won't believe it is technically possible. We don't have enough liberations under our belt to prove that it is possible. I would expect a result like Panama. I trust the majority of Iranians to manage their affairs. But you won't believe it until you see it.
We contributed a great deal to the Iranian people's previous suffering under the Shah. Let's not repeat the gift.
If you think the US is responsible, partly or fully, for the predicament that the Iranians find themselves in, then that's even MORE reason for the US to fix the problem. The Iranian people yearn for freedom, but they have no way to defeat automatic weapons. The same thing that stopped the Iraqis succeeding in their 1991 uprising. The same thing that stopped the Chinese in 1989.