Which side lawmakers take in the debate over passing new Iran sanctions legislation when they return from recess depends largely on how they answer one question: Would a new bill drive Tehran away from the negotiating table over its nuclear program, or strengthen the United States' hand?
That scale has a complex array of factors weighing down each side, with the public pronouncements of Iranian officials and the Obama administration at odds with some lawmakers' inherent distrust of Tehran and wariness about the executive branch's lobbying against additional sanctions.
Members of Congress backing new sanctions assert confidently that they believe the threat of additional economic penalties will give leverage to the United States and the group of other countries negotiating a long-term deal with Iran to end its pursuit of a nuclear bomb.
But the only cliff Mark Dubowitz of the Foundation for the Defense of Democracies sees is for Iran, if it walks away from negotiations, at a cost of $50 billion in new sanctions. "It could be devastating," he said.
"It's a common negotiating tactic to threaten to walk away from the table," Dubowitz said. "We've all threatened to walk out of a car dealership if they don't lower the price. This is like the oldest trick in the book."
Dubowitz said that by emphasizing the threat of Iran walking away, the administration and lawmakers who do so are enhancing Iran's negotiating strength. Pillar said, though, that new sanctions legislation would at minimum force Iran to take a tougher negotiating stance, similar to how any equivalent Iranian threat to install new centrifuges should sanctions fail would force the United States to take a tougher negotiating position.
Iran already demonstrated its anger with new U.S. actions targeting individuals and companies under existing sanctions on Dec. 12 by stepping away from negotiations on implementing the interim agreement.
But the terms of the congressional debate could change over time from weighing the effect of new sanctions to weighing other aspects of the bill, such as language in the Senate measure that would set forth congressional goals for a final agreement with Iran.
"That seems to be the argument so far," Dubowitz said. "They could all come back in January and it could shift to the parameters of the end state." That could be an awkward topic for the administration to debate, Dubowitz said, because they might have to defend a less strict position than Congress has in mind.