Barack Obama said during his 2012 presidential campaign that "as long as I'm president of the United States, Iran will not get a nuclear weapon."

There's been a lot of debate about how effective Obama's approach has been in halting Iran's program to develop a nuclear weapon. But this promise is narrower. The key question for judging this promise is whether, as Obama nears the end of his tenure in the White House, Iran currently has one or more nuclear weapons. And that question is far less controversial -- the overwhelming evidence is that as of today, Iran is not a nuclear-armed state.

The big development since our previous update to this promise was the nuclear deal struck between the United States, key allies and Iran in July 2015. At root, the agreement lifts international economic sanctions on Iran in exchange for it agreeing to curb nuclear technologies and allow inspections for 10 to 25 years.

Specialists say the best evidence indicates that Iran does not presently have a usable nuclear weapon.

"I think a reasonable analysis would show that they do not," said Richard Nephew, a Columbia University foreign-policy specialist who earlier served as Obama's Iran director at the National Security Council.

Ted Bromund, a foreign policy specialist at the conservative Heritage Foundation who is not a fan of the Iran deal, concurred.

"You can test a bomb on a computer if you know what you are doing, but most nuclear programs -- such as India, Pakistan, and China, and indeed the U.S. and the former Soviet Union -- want to test in real life initially," Bromund said. "So if Iran does not test a bomb by Jan. 20, 2017" -- the day Donald Trump is inaugurated -- "the odds are good that they do not have one."

For Nephew, a key piece of evidence is nuclear material. "There has been no report of a significant quantity of weapons-usable material being diverted in the country, and this is going back many, many years," he said. In addition, evidence gathered from nuclear negotiations with Iran produced "no indications that Iran has undeclared facilities capable of producing such material or fashioning a nuclear weapon."

We should note that it would be a bridge too far to say that Obama deserves all of the credit for keeping this promise. That's because the effort to keep a nuclear weapon out of Iranian hands did not start with Obama.

"The U.S. and its allies undertook a wide range of measures long before he took office that damaged Iran's ability to produce a bomb," Bromund said. These included the assassination of nuclear scientists, a wide-ranging sanctions regime, and electronic sabotage, he said. A good example is the project known as Stuxnet. It began under President George W. Bush in 2008 and is reported to have destroyed a significant number of Iranian centrifuges, greatly slowing and complicating Iran's path to a nuclear weapon..

"While it is not easy to assess the collective effect of these (pre-Obama) measures, they certainly deserve some credit," Bromund said. He added that it's possible to say with some confidence that without such efforts, Iran's "chances of success would have been higher, perhaps significantly higher."

Critics of the nuclear deal argue that it may be able to delay Iran's acquisition of a nuclear weapon, but not preclude it forever. Even supporters acknowledge that risk. But Obama's promise was limited to keeping Iran nuclear-free during the rest of his tenure in office, and it appears that that has been accomplished. So we rate this a Promise Kept.

The threat of a nuclear Iran played an important part in the foreign policy debate between President Barack Obama and Republican nominee Mitt Romney in 2012. During the debate, Obama called on Iran to "re-enter the community of nations" by giving up their nuclear program. But he also said that the "clock is ticking" and time for negotiations is running out. Then Obama promised that "as long as I'm president of the United States, Iran will not get a nuclear weapon."

It's not possible to issue an ultimate rating on this promise until the end of Obama's term. However, we thought we would review recent events in Iran in light of Obama's promise.

As we have previously noted, Iran has faced U.S. sanctions since its 1979 Islamic revolution. The United Nations and other nations have repeatedly tightened sanctions since 2006 in response to Iran's efforts to develop a nuclear weapon.

The circumstances have since then changed significantly. President Mahmoud Ahmadinejad, widely considered a hardline, was replaced by Hassan Rouhani this summer. Rouhani, a former nuclear negotiator, presented himself as a different and more moderate leader at the United Nations General Assembly in New York last month, refraining from verbal attacks on Israel, while his chief of staff met with influential American business leaders (both firsts!).  

In New York, Rouhani actively tried to lower tensions with the West. "Nuclear weapons and other weapons of mass destruction have no place in Iran's security and defence doctrine, and contradict our fundamental religious and ethical convictions," Rouhani said in front of the U.N. General Assembly on September 24. Two days later he spoke at the U.N. nuclear disarmament meeting and concluded that "no nation should possess nuclear weapons."

Rouhani is also the first Iranian president to have an actual conversation with an U.S. president in over 30 years. On Sept. 27, Obama called Rouhani and they spoke by telephone for about fifteen minutes.

The talk was met with criticism in Tehran, but its importance should not be underplayed:  "The biggest taboo in Iranian politics has been broken. This is the beginning of a new era," Ali Vaez, a senior Iran analyst at the International Crisis Group, told Reuters.

In 2010, Obama kept one of his original campaign promises by strengthening the Nuclear Non-Proliferation-Treaty. In his second term, the administration has not pursued any new sanctions against Iran, but the existing ones remain intact and continue to deeply harm Iran's economy.

According to one of our previous fact-checks oil exports, which fund nearly half of Iran's government spending, have fallen by about half since 2011, from about 2.5 million barrels a day to about 1.25 million. The drop has been driven by a European Union embargo and U.S. pressure on Iranian oil customers. The sanctions have also resulted in a high unemployment rate and a drop in Iran's currency. (Read more about it here.)

Rouhani and his new moderate approach can be seen as a direct result of the international sanctions against Iran. But politics in Tehran are extremely complicated. While Rouhani might be the elected president, the real power lies in the hands of Ayatollah Ali Khamenei, Iran's Supreme Leader – a fact that Israeli Prime Minister Benjamin Netanyahu pointed out on CBS's Face the Nation.

Israel is concerned about the shift in Iran's rhetoric and has repeatedly warned the United States and its allies to be skeptical and not to trust Iran. In a passionate speech at the U.N. General Assembly, Prime Minister Netanyahu described the difference between Rouhani and his predecessor: "Rouhani doesn't sound like Ahmadinejad but when it comes to Iran's nuclear weapons program the only difference between them is this: Ahmadinejad was a wolf in wolf's clothing. Rouhani is a wolf in sheep's clothing. A wolf who thinks he can pull the wool over the eyes of the international community."

Netanyahu is not the only one concerned: David Albright, a physicist and the founder of the Institute for Science and International Security, testified before the U.S. Senate Committee on Foreign Relations in early October 2013.  According to his assessment, Iran has the technology to build nuclear weapons but isn't moving forward at the present moment. His concern, however, is that within a few months the country could have the ability to  "build a nuclear weapon so fast and quickly that they don't have to fear military strikes before they are finished."

At this point, the Obama administration keeps pursuing diplomacy. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif met in New York in September, and Kerry has since stated that it would be "diplomatic malpractice of the worst order" not to at least test Iran's true willingness to stop its nuclear program.

At the same time, President Obama made it clear that military action is not off the table. In an interview on ABC's This Week about not launching attacks against Syria, he noted that "the nuclear issue is a far larger issue for us than the chemical weapons issue."

Representatives from Iran and the European Union-chaired P5+1 group (the United States, Britain, France, China and Russia, plus Germany) met on October 15-16, 2013, in Geneva. According to Catherine Ashton, the EU's top foreign policy official, the two-day  meeting was  the "most detailed talk ever" on Iran's nuclear program. After the meeting, White House spokesman Jay Carney said Iran had shown a "level of seriousness and substance that we have not seen before." The confidential Iranian proposal to the group will be further discussed in November 2013.

Obama said during the campaign that Iran would not get a nuclear weapon under his watch, meaning that we cannot effectively rate his promise until 2016. For now, we rate it In the Works.