Sworn enemies for 34 years, Iran and the U.S. will meet in the latest round of talks over Iran's controversial nuclear program.
Last week, the world's top diplomats diverted their planes to Geneva because of word of a breakthrough on a historic deal.
Today, the same negotiators are back at it in the Swiss city and hoping to clinch an agreement. For nearly a decade, Iran and world powers have played a cat-and-mouse game over Iran's nuclear program. Iran says its uranium enrichment program is for peaceful purposes. But the U.S. and its allies worry Iran is secretly developing a nuclear weapons program.
Since September, Iran has been on a charm offensive and the U.S. has cautiously pursued a new chapter in U.S.-Iran relations – a development made all the more remarkable against the backdrop of the long and sordid history between the two countries.
Cutting deals: missiles, money and hostages
Few moments in U.S.-Iran relations quite match the Iran-Contra affair.
U.S. anti-tank missiles were clandestinely sold and shipped to Iran in the 1980s through Israel, the proceeds used to fund anti-Communist forces fighting in Central America – all in the hope that it might secure the release of half a dozen U.S. hostages being held in Lebanon by Iranian-backed groups.
U.S. laws were broken, Congress bypassed and when the scandal broke high-level officials in President Ronald Reagan's administration resigned and were eventually convicted.
For all the anti-Western rhetoric, the Iran-Contra affair also showed that, for the mullahs, some deals were worth cutting. Iran was in the middle of gruelling war with Iraq and needed weapons.
"Simply put, there was a cake on the mission"
In 1986, a U.S. delegation carrying falsified Irish passports arrived in Tehran in the middle of Ramadan reportedly carrying gifts that included a key-shaped chocolate cake purchased at a kosher bakery in Israel.
The cake was meant to signify the hope of an opening between the two countries. In the end, the dialogue with Iran never did succeed.
In journalist Ann Wroe's account of the surreal mission in Lives, Lies and the Iran-Contra Affair, there was no senior official – or anyone for that matter of political importance – present to greet the American delegation. The cake was taken away by members of the Revolutionary Guards and eaten, she added.
"Simply put, there was a cake on the mission," Robert McFarlane, Mr. Reagan's former national security advisor, told the ABC Nightline program in 1987. "I didn't buy it, bake it, cook it, eat it, present it or otherwise get involved with it."
Dialogue of civilizations
In 1997, Iranians propelled a reformist, erudite and moderate cleric to a landslide victory in elections.
President Mohammad Khatami told CNN in 1998 that he looked forward to creating a "crack in the wall of mistrust."
The Clinton administration was eager for direct talks with Iran. But Mr. Khatami was not interested.
Instead, he spoke of the need for a global conversation among ordinary people to prevent conflict – a vision that led to 2001 being declared UN Year of Dialogue among Civilizations. Writing in the Guardian newspaper this year, Mr. Khatami admitted his dialogue had largely failed.
Almost saying "sorry"
U.S. leaders have come awfully close to an apology without ever saying sorry.
In 1999, then-President Bill Clinton acknowledged Iranian anger and spoke of how Iran had "been the subject of quite a lot of abuse from various Western nations."
A year later, his secretary of state, Madeleine Albright acknowledged that the U.S. had played a "significant role" in the 1953 coup that overthrew a democratically-elected prime minister, Mohammad Mossadeq, and that it was a "setback for Iran's political development."
Tehran dismissed Ms. Albright's near-apology as "deceitful and belated."
Axis of evil
In a State of the Union address just months after the 9-11 attacks, President George W. Bush described Iran, Iraq and North Korea as belonging to an "axis of evil" that threatened the world because of its pursuit of weapons of mass destruction.
A year later, a U.S.-led coalition went to war to disarm Iraq and the threat of U.S. military action has hung over Iran ever since.
Some Iranians see a missed opportunity for U.S.-Iran relations. Both countries despised the Taliban regime in Afghanistan and there were openings for greater co-operation post 9-11, they say.
But the "axis of evil" speech put Iran on notice.
"A new beginning"
Mahmoud Ahmadinejad stepped on to the international stage in 2005 after being elected president and used it to attack Western powers, declare the absolute right of Iran to pursue nuclear technology and to take an aggressive anti-Israel stance replete with Holocaust denials and threatening language.
The 2008 election of Barack Obama, who said during the campaign that he would meet with leaders of so-called pariah nations, offered hope of a new chapter in U.S.-Iran relations. After his inauguration, Mr. Obama spoke directly to Iranians in an Iranian New Year message and offered a "new beginning."
But the thaw never happened.
Comments by Mr. Obama about the disputed 2009 presidential elections in Iran were seen as meddling in Iran's affairs and U.S. concerns that Iran was responsible for killing U.S. soldiers in Iraq and aiding Hamas, Hezbollah and the Syrian regime made direct talks virtually impossible.
A 15-minute phone call
In U.S.-Iran relations, the 15-minute phone call between Barack Obama and Hassan Rouhani on a Friday in late September of this year – as the Iranian president's entourage drove to the airport from the United Nations General Assembly in New York – was a historic first.
U.S. and Iranian leaders had not spoken directly since the tumultuous days of the Iranian revolution in 1979 when U.S.-Iran relations ruptured.
With ultimate power resting with Iran's supreme leader, Ayatollah Ali Khamenei, any change in U.S.-Iran relations will require his approval.
Leading up to the historic telephone call, Mr. Khamenei talked of Iran's "heroic flexibility" as a "very good and necessary" tactic.
Whether a historic phone call leads to a historic agreement is now being tested.
Diplomacy through social media
As talks resume in Geneva between Iran and Western powers, watch for the diplomacy that takes place over social media.
Israeli Prime Minister Benjamin Netanyahu has been among the most active by taking to Twitter and warning Western countries against striking a bad deal with Iran.
But he is not alone.
Iranian Foreign Minister Javad Zarif tweeted shortly after U.S. Secretary of State John Kerry said that a near deal fell apart because the Iranians walked away from the table: "Mr. Secretary, was it Iran that gutted over half of US draft Thursday night? and publicly commented against it Friday morning?"
The tweet was fodder for the Daily Show's Jon Stewart.
"He tweeted? We haven't talked for 34 years, we get together, and you f--king tweet a breakup?" joked Mr. Stewart.