Say the truth: no evidence of Iran having or searching the bomb.

Because a possible invasion or war with Iran would bring to the whole area a big conflict of interests that can involve the action of Russia or/and China. The results would be catastrophic for the entire world.
Besides, there are inspectors in Iran, who hasn't done anything against international laws so far. Any type of intervention is a one-side decision that can bring in the future responsabilities over the potiticians and the county who attacks another.
Say the truth about Iran as US Defense Secretary states here: Panetta admits Iran not developing nukes

http://www.rawstory.com/rs/2012/01/09/panetta-admits-iran-not-developing-nukes/