At Truthout, Gareth Porter writes that, at this point, it’s sanctions, not enrichment capability, that’s blocking a nuclear deal between Iran and the United States.

Serious negotiations on the issue of enrichment capacity have been going on ever since an agreement between Iran and Russia on sending a large part of Iran’s stockpile of low enriched uranium (LEU) to Russia to be converted into fuel plates was concluded. That arrangement could reduce Iran’s LEU stockpile to zero, thus having the same impact on Iran’s capability for “breakout” as the dramatic reduction in Iran’s operational centrifuges the Obama administration had been demanding all summer.

But

… the US negotiating stance on sanctions relief, as revealed in public statements and leaks in recent weeks, presents political problems for Iran that make it a nonstarter.

The Obama administration acknowledges that it must provide some incentive for Iran to sign the agreement in the form of upfront sanctions relief. … but a number of US unilateral sanctions would not be suspended, and UN Security Council sanctions would remain in place for at least several years. Those positions have elicited strong objections from the Iranian delegation.

As you can imagine

“The Islamic Republic of Iran will not accept the remaining of even one sanction in the comprehensive nuclear agreement,” Deputy Foreign Minister Seyed Abbas Aragchi declared Oct. 25.

Why exactly does the Obama administration want to “delay the lifting of Security Council sanctions and obtaining Congressional authority to lift unilateral sanctions until the end of the agreement”?

The objective is said to be to gain additional leverage over Iran’s implementation of the agreement.

It’s not just the Obama administration and Congress that are making it difficult for Iran to reach an agreement, it’s also the International Atomic Energy Agency. At the National Interest, regarding the “possible military dimensions” to Iran’s nuclear energy program, Yousaf Butt asks:

…why is the IAEA pressing Iran on dubious evidence garnered from adversarial intelligence agencies and not accepting Iran’s contention that at least some of the evidence could be forged, as even a former IAEA director and inspector argue may be the case?

The answer may be simple, if surprising: there is not much nuclear-weapons expertise at the IAEA. And for good reason: the Agency’s safeguards job has to do with nuclear-materials accountancy, not nuclear weaponry. Nuclear-materials accountancy involves the timely detection of diversion of nuclear material from peaceful activities and the Agency is highly skilled in this duty. Importantly, it has never accused Iran of diverting such material to any weapons program.

But what is currently happening is that IAEA nuclear-material-accountancy experts are trying make technical judgments on weaponization work with which they are not familiar.

. . .  And this appears to be a problem in general with the IAEA safeguards section: management depends on one or two people to make key judgments. So, for example, they may turn to a single centrifuge expert on staff for all answers and advice. Instead, management should be soliciting a variety of opinions, red teaming, co-coordinating with knowledgeable staffers in other sections and should generally be more open to constructive criticism, both from within the Agency and from outside analysts.

Butt further explains that the few inspectors with nuclear-weapons experience at the IAEA are not allowed to work on Iran’s case. Why?

… because Iran objects to Western inspectors. Odd as it may seem, IAEA member states are allowed to veto certain inspectors from inspecting their facilities. In fact, states may forbid all inspectors of certain nationalities from working on their files.

Iran, for instance, has a blanket ban on IAEA inspectors from the United States, United Kingdom, France, Canada, Germany and possibly other nationalities.

This is where

Iran may be shooting itself in the foot: by barring these people from examining its file, Iran may be excluding those very people who have sufficient weapons knowledge to exonerate it from the trumped-up claims.

Lacking enough experts, including those acceptable to Iran, Butt concludes:

…the IAEA should revisit whether it will continue to press Iran on the PMD issues, and not accept Tehran’s contention that some of the material is forged. If, instead, the Agency wants to pursue Iran on this, it should urgently vet the PMD file using qualified, outside weapons experts.

When it comes to whether or not the United States and Iran can reach a nuclear deal, all you really need to read are Gareth Porter and Yousaf Butt.