Both Washington and Teheran have confirmed that a seventh round of Iran nuclear talks will start on November 29, in Vienna, Austria.

In spite of the fact that the talks will continue to officially be between Iran and other remaining parties to the 2015 Iran nuclear deal, and the United States will be participating "indirectly", the upcoming engagement will be about Iran and the US recommitting to the landmark deal, which is critical to a negotiated end to the Iran nuclear issue.

This indication of a shared interest in salvaging the hard-earned deal is a precious ray of hope after Teheran suspended negotiations on a return to the Joint Comprehensive Plan of Action in June.

The deal, which offered Iran sanctions relief in exchange for constraints on its nuclear program, was embraced globally as a significant step toward a political solution to the Iran nuclear crisis, but it has been in danger of falling apart after the wayward Donald Trump administration pulled the US out and reimposed sanctions. In response, Iran has rolled back from some of its treaty obligations.

But for all the impressive advances it has made in its nuclear pursuit, Teheran has found itself under debilitating economic pressure. And, in President Joe Biden's own words, his country, too, is suffering from his immediate predecessor's reckless move to withdraw from the deal.

That both parties have come to terms with the deal's win-win nature and potential and made the rational choice to try to reinstate it is no doubt welcome news to each other, and to regional and global peace. But unless both parties demonstrate flexibility in the Vienna negotiations, meaningful progress will be difficult to achieve. After all, neither party has shown any change in their respective stances regarding what they expect from the other side.

As Iran's top nuclear negotiator, Ali Bagheri Kani, tweeted Wednesday, Teheran will come to the negotiating table "aiming at removal of unlawful & inhumane sanctions". And it wants a US guarantee there won't be a repeat of what Trump had done. However, while indicating a willingness to return to the deal, Washington has made Teheran's full compliance with the agreement's restrictions on nuclear weapons development a precondition of its rejoining.

In an Oct 30 joint statement, the leaders of France, Germany, and the United Kingdom and the US also highlighted Biden's "clearly demonstrated commitment to return the US to full compliance with the JCPOA and to stay in full compliance, so long as Iran does the same", and expressed the belief that "it is possible to quickly reach and implement an understanding on return to full compliance".

But the four leaders are counting on Iran to change course, which looks unrealistic unless the US is willing to do the same, as Iran insists.

For the talks to actually make progress, both parties need to think how they will reciprocate if one side shows flexibility.