President Trump issued a blunt threat to Iran on Sunday morning, warning Tehran he would order military strikes if it does not rein in its proxies in Lebanon, a declaration that landed just as Vice President JD Vance arrived in Switzerland for nuclear negotiations that had already been delayed two days by escalating tensions.
The warning, posted to Truth Social, left no room for diplomatic ambiguity. Trump wrote that Iran "must immediately stop their highly paid PROXIES in Lebanon from causing trouble," adding: "If they don't, we'll hit Iran very hard again, just like we did last week, only harder!!!"
The threat came against the backdrop of a fragile memorandum of understanding finalized last week between Washington and Tehran, an agreement that reopened the Strait of Hormuz, waived U.S. sanctions on Iranian crude oil, and gave both sides 60 days to negotiate the future of Iran's nuclear program. That framework is now under severe stress, as The Hill reported, with renewed fighting between Israel and Hezbollah in Lebanon threatening to collapse the diplomatic window before the ink is dry.
The nuclear talks in Switzerland were originally scheduled for Friday. They slipped to Sunday after Iranian officials signaled Saturday that they would close the Strait of Hormuz, the waterway through which roughly a quarter of the world's oil travels, over what Tehran called violations of the Lebanon ceasefire agreement.
Even the Sunday session did not hold. The New York Post reported that Iranian negotiators abandoned the peace talks after just 80 minutes, walking out in response to Trump's escalating rhetoric. U.S. officials insisted the talks were still ongoing, but the walkout underscored how narrow the path to agreement has become.
Trump's approach has been consistent: apply maximum pressure and leave the threat of force on the table at every turn. He had already called off strikes on Iran earlier this month after announcing a broad deal had been approved "at the highest levels." That restraint appears to have its limits.
In an interview with Fox News correspondent Trey Yingst on Sunday, Trump went further than his social media post. He threatened to seize the Strait of Hormuz outright if Iran did not cooperate, telling Yingst: "We may take over the strait, if we have to. I'll blow the s*** out of them."
He also floated economic leverage: "If they don't make a deal, we'll collect tolls."
The memorandum of understanding was supposed to be the foundation for a broader diplomatic resolution. Its terms immediately waived U.S. sanctions on "Iranian crude oil, petroleum products and derivatives, and all associated services", a significant concession designed to bring Tehran to the table. In exchange, both sides committed to a 60-day negotiating window on Iran's nuclear program.
But the MOU's viability depends on conditions on the ground, and those conditions have deteriorated rapidly. Renewed fighting between Israel and Hezbollah in Lebanon gave Iran a pretext to threaten Strait of Hormuz closure, which in turn prompted Trump's escalation. Each side now accuses the other of violating the spirit of the agreement before substantive nuclear talks have even begun.
Iran made the Lebanon ceasefire a priority condition during the peace process. Iranian officials argued that strikes in Lebanon violated the ceasefire agreement, a position that, whatever its legal merit, gave Tehran leverage to delay and disrupt the talks.
The question now is whether the 60-day clock means anything at all. Trump has warned Iran before that "the clock is ticking" on nuclear negotiations. The pattern, threat, counter-threat, delay, near-collapse, resumed talks, has repeated itself for weeks.
Vice President Vance struck a markedly different tone on Sunday. Speaking to reporters after arriving in Switzerland, Vance projected optimism despite the chaos swirling around the negotiations.
"We're all working towards regional peace. There, of course, are going to be sometimes disagreements about precisely how to get there, but I actually feel pretty great about where we are in Lebanon."
He acknowledged the difficulty ahead, "There's still some additional wood to chop, but we're going to keep on working at it", but his language was calibrated to keep the diplomatic door open even as Trump was slamming it shut on social media.
Newsmax reported that Vance, at what has been called the "Lake Lucerne Summit," framed the choice in broader terms: "Can we turn over a new leaf? Can we change relations in the Middle East permanently, or do we go back to doing things the old way, which is not our preference, but is certainly very much something that can happen."
The division of labor appears deliberate. Vance keeps the process alive; Trump keeps the pressure on. Whether that dual approach produces results or simply gives Iran an excuse to stall remains to be seen.
Vance was not only meeting with Iranian-side negotiators. On Sunday, he sat down with Pakistani Prime Minister Shehbaz Sharif and Pakistan Army Chief Field Marshal Asim Munir outside Lucerne. Special Envoy Steve Witkoff and Jared Kushner, Trump's son-in-law, joined the meeting.
Pakistan has positioned itself as a key mediator in the broader Middle East conflict. The meeting signals that Washington sees Islamabad as a potential back channel, or at least a stabilizing presence, as direct U.S.-Iran talks grow more volatile.
The Washington Examiner reported that Sharif has been actively brokering peace talks and calling for a two-week extension of the negotiating deadline in exchange for Iran reopening the Strait of Hormuz. That proposal, if real, would give both sides breathing room, but only if Trump is willing to accept a longer timeline.
Trump's track record suggests he is not. He has consistently held firm on red lines in Iran negotiations, even when advisers and allies have urged flexibility.
The stakes extend well beyond the negotiating table. Fox News reported that Iran launched missiles and drones at Kuwait and Bahrain, both of which host U.S. military facilities, including the U.S. Navy's Fifth Fleet headquarters in Bahrain. Kuwait's Ministry of Defense and Bahrain's Interior Ministry confirmed the attacks, which represent one of the broadest Iranian strikes on Gulf states since the conflict began.
That escalation raises the prospect that Iran is not merely posturing over Lebanon but actively widening its retaliatory reach across the region. If Tehran is willing to strike Gulf states hosting American forces, the 60-day diplomatic window looks less like a framework for peace and more like a countdown to a larger confrontation.
Trump has shown he is willing to use force. He has also shown, as recently as this month, that he is willing to pull back when a deal materializes. The tension between those two instincts defines the current moment.
Senator Lindsey Graham, for his part, has predicted the diplomacy will ultimately fail and that Trump will take the strait by force. Trump brushed off Graham's concerns over the Iran deal at the G7 just days ago, warning the senator he'd "be in big trouble" for pushing back. That exchange captures the administration's posture: no dissent tolerated, no retreat signaled, and no guarantee the deal survives the week.
Several questions remain unanswered. What specific military action did the U.S. take against Iran "last week" that Trump referenced in his Truth Social post? What precise strikes in Lebanon did Iranian officials cite as ceasefire violations? Did the Sunday talks resume after the Iranian walkout, or have they collapsed entirely? And what official role, if any, does Jared Kushner hold in the diplomatic delegation?
The MOU text is available, but its operative details beyond the sanctions waiver and 60-day timeline remain largely undisclosed. The full scope of what Washington conceded, and what it expects in return, is not yet public.
What is public is the posture. Trump is betting that overwhelming pressure, including the credible threat of military force, will bring Iran to heel faster than patient diplomacy ever could. Iran is betting that regional escalation and the threat of oil-market chaos will force Washington to blink.
One side is wrong. The next 60 days, if the clock is even still running, will determine which one.
Diplomacy works best when both parties fear the alternative. Right now, the alternative is getting closer by the hour, and the only people who should be nervous are the ones in Tehran who thought they could bluff a president who doesn't fold.