The original participants in the Iran nuclear deal are gathering in Vienna for a second round of negotiations following last week’s attempt to salvage the agreement. Last week was the first time that the group had met since former US President Donald Trump withdrew from the deal in 2018, and the first such meeting – after several failed attempts to kick-start talks – since President Joe Biden entered office pledging to seek a return to the deal. But there are limits: Iran joined on the condition that there would be no direct US–Iran talks, meaning that the other participants – the UK, France, Russia, China, Germany and the EU – have to play the role of intermediaries. By all accounts, the first round of talks which concluded last week were constructive. Two expert-level working groups were quickly formed on sanctions and nuclear issues to develop a plan for what the US and Iran would need to do to come back into compliance with the deal, known as the Joint Comprehensive Plan of Action (JCPOA). Furthermore, all parties agreed to reconvene in Vienna this week for further discussions – a positive result in and of itself. But it is also clear that significant hurdles exist to revitalising the deal. Read the full commentary published by the Royal United Services Institute at RUSI.org.