Chester has some good analysis of the coming conflict with Iran. This link takes you to part I, and this one takes you to part II.
From part I:
Before assumptions about the use of US force can be definitively stated, the critical question becomes the time horizon. What to make of this? How to define in time, the event that creates the deadline? Iran will eventually reach a point wherein it has completed the infrastructure and research necessary to manufacture a nuclear weapon. This is the point it must not be allowed to reach.
The Atlantic article gives the Iranians 3 years, with many backside-covering qualifications. A recent US News report states three to seven years. Other reports, including one referenced in the Belmont Club by Wretchard, state as little as 4-6 months before Iran has the break-out stage and can "construct nuclear bombs whenever it wishes."
As we all know from the re-election campaign, President Bush was criticized as "rushing to war" in Iraq. Agreeing with the characterization of this decision (that it was poor form to move so quickly) or not is irrelevant. Instead, assume that Bush prefers to err on the side of action, and move quickly. In this case, let us assume the time horizon for his decision is 12-18 months. In the next year and a half, the US, whether alone or with allies, must address the Iranian nuclear program once and for all, or grudgingly admit Iran into the fraternity of nuclear powers, and like it or not, live with its regime for an indefinite period of time.
[The objection that] the US military is too overstretched for an invasion of Iran at this point in time [is] more or less correct. An invasion of some size could be mounted, but the longer the invasion force stayed in Iran, the more force structure begins to catch up to it. A large-scale recall of reservists could increase the time US forces could operate in Iran, but such a move would make the United States vulnerable in other spheres of influence (Taiwan, South Korea).
As the time horizon moves further and further into the future though, this statement becomes less and less true. As Iraqi forces take more and more responsibility for Iraq's security, the forces available for an invasion of Iran increase dramatically.
President Bush has been roundly ridiculed for acknowledging that he seeks God's wisdom when confronted with decisions of great moment. Rather than criticizing him for this we should be thankful that he does, and we should be praying with him and for him that God shows him the proper course of action in the very difficult months ahead.