The Senate on Thursday passed a series of tough, unilateral sanctions on Iran, leaving one final hurdle before the bill arrives on President Obama's desk -- which could come as early as today.
The vote was 99-0.
The House has already voted on some procedural items to allow the bill to go ahead and could also clear the legislation before the day is out. [UPDATE: The House has now passed it as well, 408-8.]
The changes included requiring the president to address the potential impact of ethanol being used to enhance Iran's energy capacity. A recent Foreign Policy article by Gal Luft explained how Iran was looking to import ethanol from Brazil to make up for a potential shortfall in gasoline as a result of the impending sanctions.
A second last-minute change requires the administration to analyze the impact of Iran acquiring energy "know-how" by engaging in joint ventures for energy development. That's related to concerns that joint ventures outside Iran could aid Iran's energy sector, such as ongoing cooperation with BP as described by Time magazine's Massimo Calabresi.
There were no changes to carefully negotiated language allowing the president to exempt companies from the sanctions on a case-by-case basis.
Ultimately, both House and Senate aides are confident that the president will approve the legislation. "There's no indication he won't sign it," one senior aide said.
But the real test of the administration's commitment to the new measures will come in their implementation. Advocates of strong sanctions have accused the administration of showing reluctance to enforce the sanctions currently on the books, so lawmakers and staffers are planning to keep a close watch to see how the law is carried out.
One senior Congressional aide suggested that the administration could demonstrate its commitment to the sanctions bill without seeming to be overly punitive by selecting a couple of high-profile instances of violations and moving swiftly to make an example out of them to show the sanctions are serious.
Showing some quick successes would demonstrate to allies and offenders alike that the reality of sanctions has changed on the ground, and might convince other potential violators to rethink, the aide said. He referred to the old Chinese proverb, "Sometimes you have to kill the chicken to scare the monkey."
The administration has said little in public about when it expects the sanctions to show results, but time is a critical factor in the White House's calculations. Iran watchers speak of three "clocks" driving U.S. policy: the speed at which Iranian nuclear technology is maturing; the time it takes for the sanctions to bite, bringing Iran to the table; and the patience of regional actors.
Estimates of Iran's technical advances vary, and Iranian scientists have made uneven progress toward having the nuclear knowhow necessary to build a weapon. Some experts say Iran could get the bomb in as little as one year's time; others say it will take longer -- and that's assuming the regime in Tehran makes the decision to weaponize, and it's not clear that it has done so already.
Then there is the question of Israel, which views an Iranian nuclear weapon as an existential threat. Israeli leaders have indicated their willingness to give the U.S. strategy of sanctions and unconditional engagement a chance to work, but calls for military action will likely heat up if diplomacy fails to produce sufficient changes in Iranian behavior.
Another concern is the risk that Arab countries, notably Saudi Arabia and Egypt, will pursue their own nuclear weapons programs to compete with Iran's.