US Secretary of State Marco Rubio declared on Wednesday, 7 October 2026, that Iran will never be permitted to acquire a nuclear weapon as long as President Donald Trump is in office, while stopping short of clarifying whether Washington could accept any level of uranium enrichment under a future deal with Tehran. The remarks came during a joint press conference in Athens, Greece, where Rubio was attending the sixth US-Greece Strategic Dialogue.

The Bright Line on Iran's Nuclear Programme

Pressed on whether recent remarks by Vice President JD Vance signalled that Washington could accept Iranian uranium enrichment above zero, Rubio was unequivocal. “I don’t understand what the confusion is about the nuclear program. Iran cannot have a nuclear weapon, simple, period, and end of story,” he said. He declined to elaborate on what specific terms would be acceptable, saying he was “not going to go into the details about what would be acceptable or not.”

Rubio stressed that any agreement Washington would endorse must structurally guarantee that Tehran could never develop such a weapon. “Anything they agree to that would be acceptable to the United States has to be something that ensures that Iran will never have a nuclear weapon,” he said. “They will never have a nuclear weapon, period, not as long as President Trump is in office. And that, to us, is the bright line.”

Iran’s Military Posture and US Assessment

Rubio argued that Tehran had pursued a deliberate strategy of building up conventional military capabilities — specifically drones and missiles — to deter other nations and US forces in the Middle East from acting against its nuclear activities. He claimed the strategy was intended to hold countries across the region at risk as a deterrence shield.

According to Rubio, that effort has been significantly set back. He claimed Iran’s drone manufacturing, missile capabilities, navy, and air force had been “severely damaged,” leaving Tehran “significantly weaker militarily.” These assessments were made by Rubio and were not independently substantiated in the State Department transcript.

Economic Pressure and the Strait of Hormuz

Rubio also highlighted the economic dimension of US pressure on Iran, pointing to sweeping sanctions. “Now they’re facing crippling sanctions. Their economy is in total and complete freefall,” he said. He additionally claimed that Iran had “lost complete control of the straits,” referring to the Strait of Hormuz, and that oil flows through the critical waterway had returned to pre-conflict levels. These claims were not independently verified.

Rubio directed blame for Iran’s economic deterioration squarely at its leadership, accusing Tehran of channelling resources toward militant groups including Hezbollah, Hamas, and the Houthis rather than domestic development. “They should have spent their money on their people, and instead they spend their money on terrorism and on weapons,” he said.

Context: US-Greece Strategic Dialogue

The remarks came on the sidelines of the sixth US-Greece Strategic Dialogue in Athens, a bilateral forum covering defence, energy, trade, technology, and regional security. The dialogue itself underscores the US effort to deepen ties with NATO allies in the Eastern Mediterranean amid ongoing Middle East tensions. Notably, Greece’s geographic proximity to the region gives the venue added diplomatic resonance.

The exchange adds fresh complexity to ongoing nuclear negotiations with Iran, where the precise terms around enrichment remain a central sticking point between the two sides. How Washington ultimately defines its “bright line” in practice — particularly on enrichment thresholds — is expected to be a defining issue in any future agreement.