TEHRAN — After years of marathon negotiations and several missed deadlines, crunch time has finally arrived for Iran's nuclear talks with the United States and five other world powers.
U.S. Secretary of State John Kerry met Sunday in Vienna with Iranian Foreign Minister Mohammad Javad Zarif, their third encounter since Saturday.
As gaps remained between all sides in the talks, Zarif planned to return to Tehran for 24 hours for consultations with Iran's leadership ahead of the June 30 deadline for a deal.
An enormous amount of ground already has been covered between Tehran and Washington, old foes who once referred to each other as "The Great Satan" and a member of "The Axis of Evil," respectively.
But despite this progress, there are still red lines to overcome before a deal can be struck.
America, Britain, Russia, France, China and Germany — known collectively as the P5+1 powers — want to ensure Iran cannot produce a nuclear weapon. They are asking for thorough inspections and written guarantees, resulting in harsh consequences if Iran does not hold up its side of the bargain.
In return, Iran wants an immediate end to the economic sanctions it says have crippled its economy. It also wants to rejoin the international community and lose its image as a global pariah.
In order to do this, however, Iran needs to prove its claim that its nuclear program is for energy alone and devoid of any military aspirations.
Powerful elements on both sides remain deeply skeptical. Senior figures in Congress have warned they could trip up any pact that does not retain the power to carry out spot checks on Iranian facilities, or an agreement that lifts economic sanctions before Tehran begins to comply fully with its terms.
In Iran, hard-liners share a similar mistrust of the agreement in its current form. Supreme Leader Ayatollah Khamenei said in a speech Tuesday that sanctions should be lifted "immediately" on a deal being struck and said inspection of Iran’s military sites was "out of the question."
Despite these differences, the general consensus among analysts is that both sides have come too far to let the deal collapse at this late stage. Coming after decades of mistrust and animosity, Barack Obama and Iranian President Hassan Rouhani have shown an unprecedented amount of political will to get this deal done.
All eyes now focus on Tuesday, the deadline for a comprehensive agreement.
Here in Tehran, many residents are tired of being on the fringes of the international community, enduring spiraling prices of everyday goods and coping with limited access to certain medicines. For them, a swift deal will mean life can return to some semblance of normality.