There are much more effective ways to controlling Iran's nuclear ambitions than through sanctions. Sanctions are horrible as a policy; they usually aim to punish a countries administration and in the end serve only to hurt the middle class population. These sanctions are also going to help further incite Shiite participation in the insurgency in Iraq. Muqtada al-Sadr has already expressly stated, "If neighbouring Islamic countries, including Iran, become the target of attacks, we will support them". How do we know he will not view these sanctions as an act of war?
Sanctioning Iran while we have a massive amount of troops in Iraq is a bad policy. We are flicking matches at a can of gasoline, and eventually it is going to ignite. It could be by the inflammation of Shiite parties in Iraq, such as al-Sadr's Mahdi Army, or just a general uprising in the insurgency, but anyway it happens, U.S. troops will be suffering as a result.
Why are we not taking a stance similar to what we took with North Korea when they expressed their nuclear ambitions? We should be examining the possibilities of supplying Iran with light water nuclear reactors, just as was planned with North Korea. Of course there would be stipulations, such as IAEA oversight and abiding by the Nuclear Non-Proliferation Treaty of which they have already signed on.
Due to the quagmire in Iraq (which we solely caused), we need to treat Iran with kid gloves. Sanctions are not kid gloves. Many studies show that the sanctions in Iraq only hurt the middle class civilians and had nothing to do with damaging the countries leaders. The only conclusion I can draw is that we are taking a childish, lackadaisical response to the threat of a nuclear Iran, where a military option isn't necessary or arguably even available.
Sanctions are unsound policy and they are not going to stop Iran. Iran is not going to just sit down and accept these sanctions. They are only going to further incite an insurgency in Iraq and further tighten tensions with Iran. Use the original North Korea model, except this time lets do it right by trying not to further alienate the country that is on the verge of creating nuclear weapons. We will supply the technology of the light water nuclear reactors, all financed by Iran. The IAEA will provide over watch of the facilities. We have to come to a compromise. There is no more Sunni Iraq able to keep Shiite Iran at a stalemate.