Here's his case for military action against an Iranian nuke:
First, Iran’s militant proxies would be able to fire rockets and engage in other terror activities while enjoying a nuclear umbrella. This raises the stakes of any confrontation that they’d force on Israel. Instead of being a local event, however painful, it becomes a global one.
This I don't quite grasp. There's no question that a nuclear capacity would have one major short-term advantage for Iran: it would indeed enable it to engage in more conventional mischief in the region. But I'm not sure why this makes it a global matter. I can see why Jordan and Egypt would be rattled, along with Israel. But that's still a regional rather than a global threat? A useful test on this: would China worry? If China doesn't worry, why should the US?
Second, this development would embolden Islamic militants far and wide, on many continents, who would believe that this is a providential sign, that this fanaticism is on the ultimate road to triumph.
But what about the impact an Israeli attack upon a Muslim nation that sees its nuclear program as a mark of success and self-respect? Wouldn't that galvanize Jihadism, poison Israel's legitimacy in the Middle East for ever, and threaten the West at large? And we should beware of basing policy on how Jihadists react.
That's how we ended up in Mosul after 19 men trained in Saudi Arabia and Afghanistan killed thousands by other people's airplanes.
Third, they would be able to pose a real and credible threat to the supply of oil, to the overwhelming part of the world’s oil supply.
This is real, but are we really talking about Iran somehow preventing the Saudis from selling their oil, for example? I don't see it. In so far as such a crisis might prod the West to innovate past oil as an energy source, it might actually do a great deal to help the US economy and long-term viability.
Fourth, they may threaten to use these weapons or to give them to terrorist proxies of their own, or fabricate terror proxies.
We heard that about Saddam. It could also be said about Pakistan.
Finally, you’d create a great sea change in the balance of power in our areanearly all the Arab regimes are dead-set opposed to Iran’s acquisition of nuclear weapons. They fervently hope, even if they don’t say it, that the U.S. will act to prevent this, that it will use its political, economic, and, if necessary, military power to prevent this from happening.”
Yes, they do, because they are Sunni and are motivated by a desire to prevent a Shiite resurgence, pioneered by Iran. But why should the US have any stake in which branch of Islam survives and prospers? Why is this our problem? Again, I can see why it's a problem - and an opportunity - for Israel. But why the entire world?