Islamabad, Pakistan – Standing before reporters at the White House, US President Donald Trump was asked whether a ceasefire with Iran was within reach.

“We have an active, willing participant on the other side,” he said on Monday, adding that the proposal on the table was “a significant step” before quickly qualifying that “it’s not good enough.”

Pressed on who was leading Washington’s diplomatic push, Trump confirmed what had been unfolding through backchannels for days.

“They’re doing it along with Marco, JD. We have a number of people doing it,” he said, listing Vice President JD Vance and Secretary of State Marco Rubio among the administration’s lead negotiators for the first time.

In an administration that has struggled to project a coherent diplomatic strategy for a war it launched more than five weeks ago, Vance has largely kept a studied distance from Operation Epic Fury.

But Trump’s statement was a public corroboration of how Vance has quietly emerged as a central actor in last-ditch efforts facilitated by Pakistan to pull the US and Iran back from the brink of what could be the most devastating escalation of the war so far.

The US president threatened over the weekend to bomb Iran’s power and energy facilities if Tehran did not reopen the Strait of Hormuz, through which 20 percent of the world’s oil and gas supplies pass in peacetime, by early on Wednesday Iran time. On Monday, he launched a profanity-laced tirade against Iran on his Truth Social platform.

And on Tuesday, about 12 hours before his self-imposed deadline for Iran, Trump escalated his apocalyptic rhetoric further.

“A whole civilisation will die tonight, never to be brought back again. I don’t want that to happen, but it probably will,” Trump posted on Truth Social.

Iran’s Islamic Revolutionary Guard Corps responded by warning that all its restraints against targets would be lifted if Trump did escalate militarily, further putting the broader region on edge. Earlier in the day, Iran’s Kharg island, its main export hub, had been bombed, and Iran had struck the Jubail petrochemical facility in Saudi Arabia.

Amid the attacks and threats, sources close to the mediation efforts said attempts to get the US and Iran to agree to a Pakistani proposal for a two-stage halt to the war were still ongoing.

Whether those efforts are able to defy the increasingly vitriolic rhetoric being exchanged by the US and Iran and instead bring them closer to a peace deal will be a test of Vance’s clout with Trump and of whether his presence in the talks nudges Iran towards dialogue, the sources said.

Vance’s known role

The night before Trump spoke, officials aware of the mediation efforts in Pakistan confirmed to Al Jazeera that the country’s army chief, Field Marshal Asim Munir, had spoken with Vance, special envoy Steve Witkoff and Iranian Foreign Minister Abbas Araghchi.

The call was part of an intensive mediation effort Pakistan has led since late March. Islamabad hosted foreign ministers from Turkiye, Saudi Arabia and Egypt on March 29 in a coordinated push to end the hostilities. That meeting followed an earlier consultation in Riyadh on March 19 in which the same regional powers began aligning their approach.

Earlier, at a cabinet meeting on March 26, Trump asked his vice president to brief officials in Iran, formally acknowledging his role in the diplomatic effort.

According to Pakistani media quoting a senior civilian official familiar with the talks, a US delegation led by Vance was twice prepared to travel to Islamabad for direct discussions with their Iranian counterparts.

Both visits were cancelled at the last moment after Tehran requested more time for internal deliberations and ultimately declined to participate, according to the senior official.

Still, by last weekend, the effort had produced tangible movement. Iran confirmed receiving a ceasefire proposal, opening the door to broader negotiations. However, Tehran eventually rejected the plan, calling it “illogical”.

Why Tehran sees Vance differently

Iran’s apparent preference for Vance predates the war.

On February 26, Witkoff and Jared Kushner – Trump’s son-in-law and, like Witkoff, a real estate magnate – concluded a third round of indirect nuclear negotiations in Geneva with Iran’s Araghchi. Omani Foreign Minister Badr Al Busaidi, who mediated the talks, emerged optimistic.

“A peace deal is within our reach,” he told US-based outlet CBS News the following day, describing “significant, important and unprecedented progress”, including what he called a commitment from Iran not to stockpile enriched uranium.

“The big picture is that a deal is in our hands,” he said.

Nevertheless, two days later, US and Israeli forces struck multiple Iranian sites, launching the war. The first wave of attacks resulted in the assassination of Supreme Leader Ali Khamenei, among several other Iranian leaders.

From Tehran’s perspective, this was a second betrayal: US officials had been engaged in negotiations with Tehran in June too before Israel and then the US bombed Iran during the 12-day war.

Javad Heiran-Nia, director of the Persian Gulf Studies Group in Tehran, said Iran had initially viewed Witkoff as a moderate within Trump’s inner circle and accepted his role on that basis.

When Kushner joined the talks before the February round, Tehran saw it as a signal of seriousness, given his proximity to Trump.

“Iran’s assessment was that the US was serious about the negotiations,” Heiran-Nia told Al Jazeera.

But the US decision to join Israel in launching the war even while talks were on flipped that assessment.

“There is a feeling among Iranian officials that the pre-war negotiations were essentially aimed at buying time to complete military positioning,” Heiran-Nia said.

Western media later reported that Tehran refused to engage with either Kushner or Witkoff after the Geneva talks. CNN, quoting regional sources, said Iran viewed Vance as more sympathetic to ending the conflict than other US officials.

Heiran-Nia said internal dynamics in Iran have also shaped this preference. After Khamenei’s death, factions within the political system have competed for influence.

The war has strengthened the Islamic Revolutionary Guard Corps while President Masoud Pezeshkian’s government has been left with limited authority over strategic decisions.

Acceptance of negotiations, including Pakistan’s mediation, has come from higher levels of the Iranian system, Heiran-Nia said. However, the format remains politically sensitive.

As of Tuesday evening in Islamabad, government officials described the negotiations as being at an advanced stage.

The emerging framework envisions a sequenced process: an initial agreement to establish confidence-building measures followed by a formal ceasefire if those steps hold.

Details of these measures have not been made public, and Pakistani officials have avoided pre-empting decisions that rest with Washington and Tehran.

Iran’s ambassador to Pakistan, Reza Amiri Moghadam, signalled progress on Tuesday.

In a post on X, he said Islamabad’s “positive and productive endeavours in goodwill and good offices to stop the war” were approaching a “critical, sensitive stage”.

It was the clearest public indication yet from an Iranian official that Pakistan’s mediation had moved beyond preliminary discussions.

Yet even as diplomatic momentum built, Trump appeared to escalate his rhetoric.

On Tuesday, he posted on Truth Social: “A whole civilization will die tonight, never to be brought back again,” before suggesting that “complete and total regime change” may already be under way in Iran.

“47 years of extortion, corruption, and death, will finally end,” he added.

Politics, perception and 2028

Iran’s preference for Vance is not only about personalities. It is also rooted in his record on foreign intervention.

As a senator, Vance argued in a 2023 Wall Street Journal opinion piece that Trump’s success in office rested partly on avoiding new wars.

In 2024, he warned that a conflict with Iran would not serve US interests and would be a “huge distraction of resources”.

Days before the February 28 strikes, he told The Washington Post: “I think we all prefer the diplomatic option. But it really depends on what the Iranians do and what they say.”

Heiran-Nia said Tehran’s view of Vance rests on two factors.

First, he was seen as initially opposed to the war, even if he later aligned with the administration’s position.

Second, unlike Witkoff and Kushner, he was not involved in the negotiations that preceded the strikes.

“From a symbolic standpoint, he is more justifiable for Iran to use in justifying the process to public opinion,” Heiran-Nia said.

He added that Vance’s wartime conduct has reinforced the perception in Iran that the vice president is positioning himself carefully for a future presidential bid.

Widely seen as a frontrunner for the 2028 Republican presidential nomination, Vance must balance loyalty to Trump with scepticism towards prolonged Middle East conflicts.

Analysts noted that both Vance and Rubio face risks. Rubio’s support for the war could become a liability if the conflict drags on or ends poorly.

Vance, meanwhile, risks appearing disloyal if he diverges too far from Trump’s position.

Positioning himself as a figure who worked to end the war offers a possible path through that tension.

That calculus has not gone unnoticed in Tehran. It has “conveyed the impression inside Iran that the vice president is adopting a cautious approach to potentially play a presidential role in the future,” Heiran-Nia said. “While operating within Trump’s system, he tries to maintain an independent approach.”