The United States offered substantial political assurances that the agreement would be fulfilled

What is a substantial political assurance?

We have the text of a letter to the IAEA from the parties directly involved in the fuel swap deal: Russia, whose job would be to produce 20% enriched uranium; France, who would fabricate fuel plates; and the United States which would upgrade Iran's research reactor and probably have some role in the financing of the deal.

The United States offered substantial political assurances that the agreement would be fulfilled.

Seriously. What does that even mean? What could it possibly mean?

My best guess, and I’m dumbfounded while guessing, is that Barack Obama himself privately gave his word that he’d try to make sure the West honored the agreement. I don’t know how to express how meaningless “substantial political assurances” must appear to Iran. Because worse than if they hadn’t been given, they are insulting. This really feels like a “trade gold for candy with children” situation.

1) Bushehr has not been fulfilled, and the US is not more trustworthy than Russia.

2) The only reason it makes sense that Iran’s uranium has to be removed from the country instead of sealed by the IAEA in Iran is if the US does not plan on delivering the fuel, or at least considers that an important contingency.

3) The idea that the terms of the deal cannot be further negotiated detracts from the credibility of the West.

Iran says its willing to do a swap, if a swap would actually happen, and Iran would actually get fuel. The deal is structured to at least give the US the option of withholding fuel unless Iran makes further concessions. Why must it be structured that way?

At the end of October, the US could, and if it wanted a swap should, have ordered production of fuel plates to start. By now, three months later, enough fuel would be ready that Iran could have made the trade, secure that there is no funny business involved, in early February and Iran’s LEU would, by today, be gone.

The unescapable conclusion is that what could be a simple swap deal is complicated by the US ambition (which might as well be openly stated) of using the fuel to pressure Iran into making further concessions on its nuclear program, and giving up any military nuclear capability.

It is time to move past that. Iran is certainly not giving up enrichment and also probably will not subject the size of its uranium stock or pace of uranium production to limits set by the US in exchange for reactor fuel.

Or not. The US does not have to accept an Iranian military nuclear capability today, even though by today it is a reality. Four years from now, the US will be willing to offer a far more complete nuclear capability than it is willing to offer today. Imagine the limits Iran would have accepted on its nuclear program four years ago. A cap on its domestic uranium stock of 500 kilograms of 3.5 LEU and nothing higher and fewer than four thousand operational centrifuges could have been agreed easily at that time and Iran would probably be implementing and have ratified the additional protocols by now. A deal like that is far more than the Iranians were asking for at the time. Oh, also Iran would be making intense efforts to stabilize Iraq and Afghanistan in concert with the US by now.

The US instead has moved, sometimes ambivalently, down the road of increased hostility with Iran. Israel has benefited because the principle that countries that do not accept Israel's legitimacy and support parties that share that non-acceptance are economically punished has been maintained. I can't see how the US has benefited, or will benefit from continuing the current path.