So why aren't we bombing? Clearly sanctions are doing nothing

Iran's Nuclear Experiments Raise Alarm at UN Agency - Jay Solomon
The UN nuclear agency says it is "increasingly concerned" that Iran has conducted experimental work to develop nuclear weapons, in particular on warheads to deliver nuclear payloads. In a report issued Friday, the International Atomic Energy Agency also said Iran has begun deploying second-generation centrifuges at its largest uranium-enrichment facility at Natanz, which could allow the country to produce nuclear fuel at three times its current rate. Tehran has concurrently begun installing centrifuges at an underground site near Qom, seen as impervious to a military attack.
The IAEA said it has gained additional information indicating Iran has conducted studies on how to build nuclear weapons. The agency confirmed that Tehran had begun deploying more advanced IR-2m and IR-4 centrifuges at Natanz. (Wall Street Journal)