I would say that 2,400 dead, 17,000 wounded and $450 billion in war costs are sufficient evidence of "toughness".
It will be a wasted sacrifice if Iran gets a nuclear weapon and destroys Israel. After all, this is why we got rid of Hussein. If Iran does it anyway, all of this will have been in vain.
And many of those dead are dead because of Iranian supplied cash or weapons or training or all of the above.