Trust in decline: What to know about the 5th round of U.S.-Iran nuclear talks?

Iran and the United States will hold their fifth round of talks on Tehran's nuclear program this Friday in Rome, Italy.

U.S. Special Envoy to the Middle East Steve Witkoff will lead a delegation in discussions with Iranian Foreign Minister Abbas Araghchi.

Since negotiations began on April 12, the two sides have held four rounds of indirect talks focused on Iran's nuclear program and the potential lifting of U.S. sanctions – so far without any substantial breakthroughs.

In recent days, U.S. officials have repeatedly demanded that Iran fully cease uranium enrichment, an ultimatum Tehran has firmly rejected, calling the issue "non-negotiable."

Shift in attitude

The first round of indirect talks was held in Muscat, the capital of Oman, on April 12, followed by three more on April 19, April 26, and May 11. As the discussions progressed, they shifted from broad themes to technical details. By the third round, economic experts had joined the consultations.

U.S. President Donald Trump said on May 15 that the United States was getting very close to securing a nuclear deal with Iran, and Tehran had "sort of" agreed to the terms.

"We're in very serious negotiations with Iran for long-term peace," Trump said at a business roundtable in the Qatari capital Doha.

However, Witkoff said on May 18 that any deal between the U.S. and Iran must include an agreement not to enrich uranium, a comment that drew criticism from Tehran.

"We have one very, very clear red line, and that is enrichment, and we cannot allow (Iran to have) even 1 percent of an enrichment capability," he told the U.S.-based ABC News.

The U.S. previous attitude was generally interpreted as allowing Iran to carry out civilian uranium enrichment activities with a level below 3.67 percent.

Iran's Supreme Leader Ali Khamenei on Tuesday warned the United States against making "nonsensical" remarks, saying that "no one (in Iran) is waiting for permission from anyone. Iran has its independent policy and method and pursues its own agenda."

Khamenei said he expects no results from the ongoing nuclear talks with Washington.

Before the fifth round of negotiations, the level of mutual trust between the United States and Iran further decreased, and the contradictions and confrontations became more prominent, said Niu Xinchun, executive director of the China-Arab Research Institute of Ningxia University.

If neither the United States nor Iran is willing to back down from their current public positions during the fifth round of talks, the chances of the talks producing anything of value are slim, Niu said. 

U.S. media also reported, citing Israeli sources, that Israel will quickly attack Iran's nuclear facilities if the U.S.-Iran negotiations fail, adding that the attack will last at least a week.

Breaking the bottom line

The U.S. attitude shift has broken Iran's bottom line on uranium enrichment, leading to sharp confrontation between the two sides on this issue, according to analysts.

Liu Lanyu, an Iran expert at the Institute for International and Area Studies of China's Tsinghua University, noted that Iran's bottom line in the negotiations is to retain the right to carry out low-level uranium enrichment activities in Iran.

The U.S. recent shift to a "zero enrichment" policy will not only fail to help reach an agreement with Iran, but will also close the diplomatic window for negotiations, said Trita Parsi, executive vice president of the Quincy Institute for Responsible Statecraft, a U.S.-based think tank.

Witkoff may hope that Iran will stop enrichment under pressure, but this is a high-risk gamble, Parsi said, noting that Iran has never accepted a complete halt to enrichment, and there is no precedent for even temporary concessions.

Meanwhile, the scope of the negotiation agenda is also a focus of debate between the two sides.

The Trump administration is seeking to include restrictions on Iran's ballistic missile development and regional influence in the negotiations, while Iran insists that the talks should be limited to nuclear issues, with the expected goal of convincing the U.S. of the peaceful nature of Iran's nuclear program and lifting sanctions on Iran, said Zhao Beiping, deputy director of the Middle East Research Center of Shandong Normal University.

The U.S. has introduced multiple negotiating goals, making it increasingly difficult to reach a consensus, Zhao added.

Qin Tian, deputy director and research professor at the Institute of Middle East Studies of the China Institutes of Contemporary International Relations, said both countries are locked in a standoff over "who concedes first," further complicated by a deep lack of strategic mutual trust.