Administration officials say that "sanctions relief is not on the table unless and until we see substantial concessions" from Iran, says Suzanne Maloney, an Iran specialist at the Brookings Institution in Washington.
"I don't think there is really any give on the sanctions issue ... in part because in a political year, an election year, with a Congress that is very solidly behind these sanctions, it would be very difficult for the president to appear to be waffling on them at all," says Ms. Maloney.
The word "incentive" is rarely used in Washington, regarding Iran, though other measures may be offered in Baghdad.
"I do worry that there is a disconnect," says Maloney. "The Iranians from their perspective need something to demonstrate some sense of victory, and to persuade the skeptics within their own camp that there are rewards to be gained from cooperation, not just preventing any further pressure, but actually lifting some of the sense of siege."
Iran has signaled it may stop 20 percent uranium enrichment – used to fuel an existing reactor in Tehran, but also just a few technical steps away from weapons-grade material for a bomb – and cap enrichment levels to below 5 percent, to fuel ordinary power reactors.
Iran may also accept a more stringent inspection regimen by implementing the Additional Protocol of the Nuclear Nonproliferation Treaty.