Actually we do.......Professor literal though is trying to use the likelyhood that perhaps a few dozen or more might survive a mass carpet nuking. The point Plane was making though, is while we could, we wouldn't. While Isreal could seriously bring an end to Iran, they wouldn't. While if the likes of Hamas and iran had their ways, they would seriously try, starting with Israel, and working towards the U.S.
Nor is this about Iran and 911. That'd be Dr deflection yet again trying to argue a point, no one is making. Presently, Iran is sponsoring/supporting terrorist actions across the globe, specifically aimed at Israel and anything associated with U.S. interests. This isn't about Iran directly attacking the continental U.S. It's about Iran attacking anything associated with the U.S., in which case, they are attacking the U.S.
And while hypothetically a "blockade" of Japan may have eventually brought about the end of WWII, it could have also dragged on the war many more years, and would have been at the cost of thousands upon thousands of more American lives. Invasion was the only other viable option, however another option presented itself. Enough American lives had been lost, and there was an avenue to bring it to a abrubt end, using the 2 nuclear weapons that were dropped. And America is better for having done it