What he is saying is we need to strike now. If we wait, the collateral damage will be greater.
Yes, but the writer pretends that is the worst outcome. It's not. The worst outcome is if we wait a little longer, dithering and whining--probably less than a year at this point. Then it won't just be radioactivity scattered around Iran, it will be radioactivity all over the place, and tens of millions or even hundreds of millions of deaths, depending on whether the conflict can be localized.
History suggests that once things spiral that far out of control, conflicts cannot be localized.