If Iran was merely a isolated rogue nation seeking to get the bomb solely for ensuring it's survival, like North Korea, things would be different. But Iran wants to both have total regional dominance and to destroy Israel. On top of that, they are religious fanaticals, meaning I would not put anything past them.
Considering Iran can so easily "shoot dissenters on the street ... carries out mass arrests and uses torture and rape as weapons with which to oppress" to their own people, can you imagine what they would do to others, like Sunnis and Kurds?
Lets look at it another way. Lets say the Nazi's never invaded France or attempted to invade England, remaining largely territorial, but still implemented the Holocaust. In that situation, should we have sat back and done nothing? If Iran only invades Iraq, but then engages in genocide of Sunni's and Kurds, should we just ignore it because they stopped at Iraq's border?
