I've told people for a long time that the biggest reason we went into Iraq was because of the NEXT war with Iran and Syria.
You may be right and that is the strategy, but I want to debate this.
Because it is far from clear to me, why it would be a good thing to be in Iraq, if there is a strategy to move on Iran. For being in Iraq leaves us vulnerable, not strong. And whatever is the point of replacing Sadaam Hussein in order to take on the Iranians? He would have been a prime ally in such a war.
NonValueAdded points out:
Saddam playing no-fly-zone tricks, etc. He was step one.
Iraq was very weakened and miserable because of the sanctions. Sadaam would probably have accepted any deal to lift sanctions in return for support of any offensive on his eastern border. For he hated them no one hated Iran more than him.
In the long gone days when Sadaam ruled Iraq there were no militias on the streets, no no go areas, no Iranians in Baghdad bringing funding for private armies (I am thinking of SCIRI, which is part of the Iraqi government.)
The Shia areas of Iraq have been quiet. This is not because they really support the occupation the day will come for the confrontation, and they are planning long and carefully for that moment. The British head of forces in Basra recently admitted that the city is out of control, and that arms are flowing in constantly. The people with these weapons are not doing anything yet. They are accumulating and accumulating them. And accumulating their grievances, too.
In April an Ayatollah Husseini in Karbala spoke out in a sermon about Farsi speaking pilgrims in the city who looked to him like Iranian army officers on leave (or maybe not on leave). He was shot the next day and the last I heard he was half-dead in a coma.
It would be a big mistake to underestimate what the Iranian army can do, especially acting through local proxies. The Israelis were often astonished by the determination and expertise of the Hezbollah. In Iraq, they would be more formidable. They have tens of thousands to recruit from, huge areas to operate in, and US forces in Iraq are very thin, compared to the intensive Israeli presence in Lebanon.
Iraq has no real government. Iraq is a swamp. Our forces for democracy allies in Iraq are laughing at us. There is not a democratically inclined person in the whole country. They are getting a lot of money, and when things get difficult they will go back into exile. Before doing anything, taking up any foreign policy initiative, we need to settle the Iraq issue, which means somehow getting it a stable government.