Tony Karon writes: Anyone banking on a big-win breakthrough in Wednesday’s nuclear talks with Iran will likely find themselves in the same boat as investors who bet on an instant surge in the Facebook stock price last week. If there’s value to be found in nuclear negotiations with Iran, then — like an investment in Facebook — it’s likely to emerge over time. And in both cases, even the long-term outcome remains uncertain.

After weeks of upbeat assessments, Western officials seemed to tamp down expectations ahead of the meeting that got underway in Baghdad on Wednesday. “If we talk substantively on elements of a deal and agree to meet again in three weeks, Baghdad will have been a success,” a senior U.S. official told al-Monitor on Monday. The spin ahead of the talks in recent weeks has been positive — almost too positive for diplomats, who naturally prefer diminished expectations. At home, Iran’s leaders are proclaiming a great victory in the willingness of Western powers to negotiate while Iran continues to enrich uranium, suggesting that they’re preparing their public for a compromised deal that will be sold as a great victory. The Western narrative paints Iran’s willingness to negotiate as a consequence of ever tightening economic sanctions, implying that such pressure must be maintained to curb its nuclear ambitions.

There are some positive signs: Sunday’s talks in Tehran between IAEA chief Yukiya Amano and Iran’s nuclear negotiator Saeed Jalili appear to have yielded an in-principle agreement, not yet inked or finalized, to expand the nuclear-watchdog agency’s access to sensitive sites in Iran. Amano, who has taken a tough line in dealing with Iran, was upbeat, expecting a signed agreement “quite soon.” But the IAEA talks are the undercard to the negotiations between Iran and the P5+1 (the U.S., France, Britain, Germany, Russia and China). Even if they improve the atmosphere for the Baghdad meeting, a breakdown between Iran and the P5+1 would likely imperil any progress made by the IAEA.