>>1. Agression will induce more agression. [...]
>
>Tell that to Iran's president, Osama Bin Laden, the Taliban, Hamas, the terrorists. Who started?

No fingers pointing west for anything at all?


>>2. It serves no military goal, other than it will enforce Irans decision to develop nuclear weapons and will use arguments of the right to defend itself.
>
>But what if such a fierce attack on Teheran effectively destroys Iran's capacity to further develop nuclear weapons? In that case it would be a military (and political) goal.

It would serve only to destroy Tehran and probably the current government of Iran. Nothing more.


>>3. It will have a negative effect on the US image world wide as it now would reflect the strong muscled guy who acts like an elephant in a chinashop.
>
>A negative effect on who? Do these people think positive about the US now then?

It will legitimize the use of WMD by all sides and for any reason perceived as just by the attacker.


>>4. Nations like china, north korea and even russia will build up their military forces and expand their influences as they realise that they could be next.
>
>Do the US currently threaten China and Russia? Why should they feel they might be next? They might also decide to cooperate.

It would legitmize the use of WMD and hence send a clear message to any nation which opposes the will of the US.


>>5. The international finance market could react [...]
>
>It will sure do. But if it results in a lessening of the threat that Iran poses, it may well lead to a positive effect after a while.

It will galvanize the Muslim world and give justifcation and focus for all their hatred and anger.


More significantly - the very fact that a nuke has not yet been dropped on Tehran is itself confirmation by the US military and government that they themselves do not feel the pros outweigh the cons otherwise it would have been done already. They surely understand more about the ramifications of such an act than anyone else, especially us laymen which, I assume, includes your pro-nuking friend.