Biden's inaugural speech focused mainly on healing domestic rifts and a new kind of politics at home. But he also signalled a return to engagement with the outside world.
Much will depend on Iran’s response to what it sees as Israeli and US provocation, including the November assassination of an Iranian nuclear scientist.
A new US administration needs to rejoin the nuclear deal and engage in statecraft to improve relations with Tehran.
Biden and Trump are like night and day on foreign policy, and American global engagement would change radically under a Biden presidency. But actual Mideast policy might show only cosmetic changes.
With a nuclear deal set to expire, ongoing tensions in the region and an uncertain US presidential election, there may soon be an increase in hostilities in the Gulf region.
In 2016 Trump promised to 'shake the rust off America's foreign policy.' Four years later, it's clearer what that looks like: a US that sits on the sidelines of world crises and collaborations alike.
The US bid to impose so-called 'snapback' sanctions on Iran was roundly rejected by the UN security council.
Some of the major events in US-Iran relations highlight the differences between the nations' views, but others presented real opportunities for reconciliation.
Since President Donald Trump took office, Iranians have held a more unfavorable view of the US.
Although neither side apparently wants conflict, tensions remain over the presence of US troops in Iraq and Iran's decision to walk away from part of the 2015 nuclear deal.
Iran has withdrawn from key elements of the 2015 nuclear deal. The UK should respond with caution – and flexibility.
Given the perils of direct confrontation with the US, the most likely recourse for Iran may be to mobilise its proxy militias to attack American assets in Iraq.
It's very dangerous to assume that Iran will not escalate the crisis further, much less that the US could limit any violence that might ensue.
President Trump's Iran policy took a dramatic turn when the US killed Iran's top military commander in a drone strike. To avoid war, one foreign policy scholar says Trump has to reverse his stance.
How policy has shifted back and forth since 1945 over the fine line between nuclear energy and nuclear weapons.
Iran's goal is to sow discord and inflict pain on energy markets, while avoiding crossing a threshold that prompts retaliation from the US. This is a fine line to walk at the best of times.
A fifth of the world's oil travels through the narrow waterway.
Iranian President Hassan Rouhani staked his political fortunes on bringing Iran out of isolation. Now, it appears he's losing control to hard-liners in Iran.
Iran has announced it will breach the limits on uranium enrichment agreed under the 2015 nuclear deal, after the US turned its back on the agreement. What does that mean for Iran's nuclear program?
The US has imposed new sanctions against Iran's top leaders, but its foreign policy has no clear focus.