'Progress' in the Iran talks -- but we've heard that before

john kerry nuclear negotiations iran vienna bts_00001913
john kerry nuclear negotiations iran vienna bts_00001913

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    6 times Kerry talked about progress on the nuclear talks

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6 times Kerry talked about progress on the nuclear talks 01:00

(CNN)Whether negotiators reach a deal on Iran's nuclear program has been in a constant state of uncertainty for months now, and some of the language used by key players has made it difficult for observers to see whether or not any progress is actually being made.

On Thursday, Secretary of State John Kerry made it clear that the U.S. is willing to walk away from nuclear talks with Iran.
Like any diplomatic relationship, it's also good to take a step back and look at the good times. Kerry and his international counterparts have been trying to hammer things out for years. Since 2014, there have been more than a handful of occasions when he has talked about the progress negotiators have made.
For example, there was the time in July 2014 when Kerry said that the countries were working in "good faith to move forward". Or the time he doubled down in March when he applauded the "genuine" and "substantial" progress.
    Thursday's remarks -- where Kerry reminded the world that the U.S. didn't have to stay, but was choosing to because of the "real progress" that was being made -- was enough to make the world scoot closer to the edge of its collective seat to see if these countries can work it out.
    As of Friday, the negotiation has been extended — yet again — until Monday.