This is Why You Talk With Adversaries, and Keep Your Word

The Iranians have put it very clearly, they do not consider the United States, or at least the US as led by Bush and His Evil Minions^™ to be a reliable negotiating partner. I agree with them Bush cannot be trusted to enter into good faith negotiations.

What's more, this is a reasonable, and rational position.

"We don't trust the United States," he told McClatchy Newspapers after the IAEA Board of Governors finished its latest round of talks on Iran's nuclear program. "We could suspend nuclear enrichment. We did it before for two and half years. But it wasn't enough then, and wouldn't be enough now. We will not suspend enrichment again because there is no end to what the United States will demand."

I agree with Matthew Yglesias's assesment, that it makes no sense to try to appease religious fanatics, so any confidence building measure is meaningless when the current US government simply cannot be trusted.