Iran has embarked on "activities related to possible weaponization," said American sources Thursday, Dec. 22, thereby accounting for the dramatic reversal of the Obama administration's wait-and-see attitude on attacking Iran. The change  was articulated this week by US Defense Secretary Leon Panetta and Chairman of the Joint US Chiefs of Staff Gen. Martin Dempsey.
debkafile's Washington sources report that the Islamic Republic crossed the red line President Barack Obama had set for the United States, i.e., when Tehran begins using the technologies and fissile materials (enriched uranium) it has amassed for assembling a bomb or missile warheads.  This marks the moment that Iran goes nuclear and only a short time remains before it has an operational nuclear weapon.
Washington has always claimed that when the order to build a weapon was given in Tehran, the United States would know about it within a short time.
The US stealth drone RQ-170 was sent into Iranian airspace for the first time to find evidence to support this suspicion. On Dec. 4 the Iranians downed the unmanned reconnaissance craft by intelligence or cyber means not yet fully clarified. The US - and most probably Israel too - then turned to other intelligence resources to find out what Iran was up to. According to debkafile's military and intelligence sources, they found evidence that Iran has in fact begun putting together components of a nuclear bomb or warhead.