But there is not much time.
"Now Iran must choose," Kerry stated.
"What will Iran choose?," the secretary wondered. "Despite many months of discussion," Kerry acknowledged "we don't know yet."
The uncertain outcome is fueled by discrepancy between public proclamations and closed-door meetings.
"We do know that substantial gaps still exist between what Iran's negotiators say they are willing to do and what they must do to achieve a comprehensive agreement. We also know that their public optimism about the potential outcome of these negotiations has not been matched, to date, by the positions they have articulated behind closed doors."
Such discrepancy, Kerry pointed out, "underscores why these negotiations are necessary and why the international community united to impose sanctions in the first place."
Kerry foresees two distinct paths ahead of Iran:
"If Iran is able to make these choices, there will be positive outcomes for the Iranian people and for their economy. Iran will be able to use its significant scientific know-how for international civil nuclear cooperation. Businesses could return to Iran, bringing much needed investment, jobs and many additional goods and services. Iran could have greater access to the international financial system. The result would be an Iranian economy that begins to grow at a significant and sustainable pace, boosting the standard of living among the Iranian population.
"If Iran is not ready to do so, international sanctions will tighten and Iran's isolation will deepen."
U.S. negotiators will continue their efforts in Vienna from now until the deadline, Kerry noted. The determining factors for for success will be "a matter of political will and proving intentions..."