the iranian armed forces wouldn't stand a chance against the americans , seeing how badly they demolished the iraqi armed forces , theres no opposition to saying it won't happen to iran.
a big difference between iran and iraq... iran is a bigger country both in terms of size and population(5 times as large as iraq) it has not been crippled by sanctions it army is better equiped than the iraqis and more fundamentalists 2. Also the terrain of iran is much more mountainous than iraq. so much easier for defensive and guerilla warfare. Should the usa ever decide to invade it would be political suicide and a potential military nightmare for them.
Um... Iraq proved that a better-equipped, better-handled army can whip the Iranian masses. And look what the US did to Iraq. Iran has had sanctions on military equipment ever since the Islamic Revolution - up until then it was buying top-grade US/UK/etc weaponry - now (20-odd years later) mostly inoperable due to lack of spares etc. Iran's only chance - like Iraq's - is guerilla / insurgent warfare.
Not to mention the ingredients supplied by the British government to Iran in the 90's for making mustard gas and nerve gas plus assorted items from France, the netherlans, Italy, Germany attempted to sell them some subs also but I think it fell through.