why not go to war with Iran now

Notice, please, there is no question mark at the end of the title. This is not a suggestion; it's an argument against a dangerously unwise policy.

In the current issue of Foreign Affairs a think-tank scholar named Matthew Kroenig argues that the United States"should conduct a surgical strike on Iran's nuclear facilities, absorb an inevitable round of retaliation, and then seek to quickly de-escalate the crisis."  He seems to feel that it's better to have an inevitable war now, with Iran still a nonnuclear power than later. 

He argues that Iran's retaliation would be manageable, and that the United States wouldn't even have to seek regime change in Tehran. Dubious! Going to war would require a large ground force and a lengthy war to defeat both the Iranian military and its enraged populace. Even if the worst consequences of retaliation could be mitigated, we would have created a permanent enemy which likely would gain many friends to work against us.

But the greatest flaw in Kroenig's article is that chimera that got or almost got American into numerous conflicts in the past -- the idea of a "surgical strike."  Civilians want to believe, and some Air Force officers do believe, that limited attacks can achieve massive changes in an adversary's enmity. More likely, history shows, you need a major war and regime change -- and then you might get lucky.

There's at least one (retired) Air Force officer who disagrees with the notion. General Michael Hayden, CIA director in George W. Bush's second term, told a group last week, "When we talked about this in the government, the consensus was that [attacking Iran] would guarantee that which we are trying to prevent -- an Iran that will spare nothing to build a nuclear weapon and that would build it in secret." Regrettably, Hayden's honesty on the issue caused a problem for the Romney campaign, to which he is a special adviser.

For another analysis of why Kroenig is wrong, read this piece by Colin Kahl.