Well, you can't blame them for a bit of posturing considering they have far more right to be concerned about what is going on in Iraq than most other countries.
Put yourself in their shoes: Imagine a coalition of Arab nations nipping over to Canada and suppressing the place and occupying it. Do you think that the Yanks over the border would just sit quietly and let it happen?
Or to put it another way:
Yes there are indeed some terrorists in Iran, and a lot of religious radicals too, as there are in quite a number of countries where Islam is the main religion. But then again, there are a lot of religious radicals and terrorists in Ireland and many other countries besides, yet you don't see the Syrian Air Force nipping over there and bombing Belfast claiming that they are fighting for peace and a war on terror, and not giving a crap about civilians being hit in 'collateral damage'.
We may not agree with their politics or their religion, but your average everyday Iranian citizen who's going out to work, paying the bills etc, can hardly be blamed for thinking 'Hey, we've got just as much right to have a Nuke as anyone else, especially with an occupying army over the border that thinks we're all a bunch of terrorists'.
An extreme example, I know. But everyone has the right to defend themself. And one man's terrorist, is another man's freedom fighter. It just depends on your point of view.
But back to the main point of this post: Yes, I think that the Iranians could put up quite a fight. If you relate it to my extreme example, who do you think is going to be more dedicated to such a fight, a US or British soldier who's been sent over to some country he doesn't really know or care about, or someone who is fighting for their homeland and has nothing else to lose?
Chock