In an effort to prevent public knowledge from slipping down the memory hole, let's just note a few historical facts with regards to Iran's nuclear ambitions.
In 2003 Iran offered to dialogue with the United States in which everything was on the table "including full cooperation on nuclear programs, acceptance of Israel and the termination of Iranian support for Palestinian militant groups." The US does not have diplomatic relations with Iran so this offer came via a Swiss diplomat.
The response from the United States was to censure the Swiss diplomat for bringing the offer. But Iran pressed on regardless. The following year they reached an agreement with the EU in which they agreed to suspend uranium enrichment. In exchange they asked for "firm commitments on security issues." Meaning, get Israel to stop threatening to bomb us.
The EU did not live up to it's end, apparently due to US pressure. So in 2005 Iran resumed uranium enrichment.
So it would seem that punishing Iran and excluding it from the world community is more important than the security of the world.