Trump warns Iran nuclear threat as 20% of oil flow at risk

President Donald Trump's warning that Iran's nuclear threat is serious undercut Vice President JD Vance's opening offer to "turn over a new leaf" with Tehran, as negotiators met at a Swiss lakeside resort to hash out the 60-day framework signed last week.

"The question before us now is how much more can we accomplish together? Can we change relations in the Middle East permanently?" Vance said at the Bürgenstock resort near Lake Lucerne, according to pool reports.

The 80-minute session between Vance, Jared Kushner, Steve Witkoff and Iran's Parliament Speaker Mohammad Bagher Ghalibaf and Foreign Minister Abbas Araghchi quickly hit turbulence. Iranian state media said talks entered a "difficult phase" after Trump posted on social media that Iran must stop its "highly paid PROXIES in Lebanon" or face strikes "much harder" than last week's. Ghalibaf responded on X that Iran's armed forces are "prepared to respond in a different manner."

At stake is the unimpeded flow of roughly 20% of the world's traded oil through the Strait of Hormuz — which Iran's Islamic Revolutionary Guard Corps claimed to have closed, a move U.S. Central Command disputed. The 60-day agreement signed by Trump and Iranian President Masoud Pezeshkian allows Tehran to sell oil freely and access billions in frozen assets in exchange for diluting its enriched uranium stockpile. Failure would risk a return to conflict that already spiked crude prices and gasoline costs ahead of peak summer travel.

Strait of Hormuz and the Oil Risk Premium

The Strait of Hormuz dispute injected the sharpest risk premium into crude markets since the war began. Iran's IRGC declared the waterway shut on Saturday, alleging U.S. and Israeli truce violations, though Vance said millions of barrels of oil have moved through in recent days. Trump separately threatened to levy U.S. tolls on the strait if no deal is reached in 60 days, posting that the money would compensate for "services rendered as the Guardian Angel to the countries of the Middle East."

The last time a similar closure threat emerged — during the 2019 tanker attacks in the Gulf of Oman — Brent crude spiked about 15% over two weeks before Saudi Arabia boosted output to stabilize markets. This time, the stakes are higher: Iran's nuclear program is more advanced, and the U.S. has already conducted strikes on Iranian nuclear sites last summer.

Nuclear Enrichment Remains the Core Obstacle

Pezeshkian reiterated Sunday that Iran "will never back down from the right to enrich uranium," a position that directly conflicts with the agreement's call for Tehran to dilute its stockpile of highly enriched uranium buried at sites targeted in U.S. strikes. Trump, in a Fox News interview, warned the Iranian president to "watch what he says" and threatened to "take over the rest of the country."

The framework gives negotiators 60 days to resolve these technical details, with Pakistan and Qatar mediating. Vance said he planned to stay in Switzerland for "a day or two," leaving Witkoff and Kushner to lead the detailed nuclear talks. The compressed timeline mirrors the structure of the 2015 JCPOA negotiations but with far less trust between parties after a year of direct U.S.-Iran hostilities.

Market Implications

For investors, the key variable is whether the Strait of Hormuz remains open. Any sustained disruption would push Brent above $90 a barrel, according to options market pricing, while a collapse of talks entirely could trigger a flight to gold and the dollar. Defense stocks have already priced in continued conflict, with the S&P 500 aerospace and defense sub-index up roughly 18% year-to-date.

The next milestone is the Lebanon ceasefire, brokered Saturday between Israel and Hezbollah, which appeared to be holding. Neither Israel nor Hezbollah are signatories to the U.S.-Iran deal, and Israeli Prime Minister Benjamin Netanyahu has vowed to keep forces in southern Lebanon until threats are eliminated — a wildcard that could unravel the broader framework before the 60-day clock expires.

This article is for informational purposes only and does not constitute investment advice.