U.S. Strikes Eliminated Iran’s Top Moderates, Hardening Regime and Collapsing Diplomacy

The February 28 U.S.-Israeli strikes that killed Iran’s Supreme Leader Ali Khamenei and the March 17 assassination of security chief Ali Larijani eliminated the regime’s most experienced diplomats at the exact moment preliminary negotiations were advancing, consolidating hardline control and erasing the West’s diplomatic off-ramp.

The targeted killings transformed what had been a promising diplomatic opening into a regime dominated by IRGC-aligned hardliners who now control both military and nuclear policy. According to international relations scholar John Mearsheimer, speaking on March 30, RealClearPolitics reported: “We have killed almost all of the moderates. In the context of Iranian politics, Ayatollah Khamenei, who we killed on February 28th, is considerably more moderate than his son.”

Larijani, Iran’s de facto leader overseeing nuclear diplomacy and regime restructuring after Khamenei’s death, represented the regime’s most experienced interlocutor with Western powers. His assassination near Tehran on March 16-17 installed a hardline Revolutionary Guard general in his place. The succession pattern was clear: Mojtaba Khamenei, IRGC-aligned and considerably more hawkish than his father, was elected Supreme Leader on March 8-9.

Diplomatic Collapse in Islamabad

The consolidation of hardline power manifested in the April 10-12 Vance-Ghalibaf talks in Islamabad, where 21 hours of negotiation failed to produce agreement on nuclear weapons commitments, Strait of Hormuz control, or Sanctions relief. Iranian parliament speaker Mohammad Bagher Ghalibaf, himself IRGC-linked, told Vice President JD Vance that “the U.S. has understood Iran’s logic and principles, and it’s time for them to decide whether they can earn our trust or not,” per Al Jazeera.

Upon arrival in Islamabad, Ghalibaf explicitly cited the assassination pattern as proof that Washington uses negotiations as cover for military operations. “Unfortunately, our experience of negotiating with the Americans has always been accompanied by failure and breaches of commitments,” he stated, according to NBC News. “Twice within less than a year, in the middle of negotiations, despite the goodwill of the Iranian side, they attacked us and committed multiple war crimes.”

Iranian demands in the talks included permanent end to conflict, regional ceasefire covering Lebanon, Strait of Hormuz control, war reparations, asset unfreezing, and complete sanctions lift. The maximalist position reflected hardliners’ confidence that energy supply disruptions gave Tehran leverage, according to CNBC.

Energy Crisis and Market Dysfunction

The diplomatic breakdown coincided with what the International Energy Agency called “the largest supply disruption in the history of the global oil market” — 10.1 million barrels per day lost in March as Strait of Hormuz flows collapsed from 20 million barrels per day to 3.8 million by early April. Physical crude prices surged near $150 per barrel, far above futures markets, while middle distillate prices in Singapore reached all-time highs above $290 per barrel.

Brent crude traded at $96.80 per barrel on April 15, per Trading Economics, down from peaks near $120 earlier in the month but still elevated enough to trigger demand destruction. The IEA projects global oil demand will fall 80,000 barrels per day in 2026 — the first decline since the 2020 pandemic — compared to prior forecasts of 640,000 barrels per day growth.

The Trump administration’s response undermined its own sanctions architecture. On March 20, the White House issued General License U temporarily waiving sanctions on Iranian oil through April 19 to stabilise markets, but without payment restrictions or price caps. The move, analysed by Council on Foreign Relations, compromised sanctions effectiveness as a coercive tool at the exact moment hardliners were consolidating control over nuclear policy.

Macro Repercussions

The International Monetary Fund models severe scenarios showing global growth reduced by 1.3 percentage points in 2026 with oil prices 80% higher than baseline. Inflation would rise 190 basis points, reaching 5.8% and potentially triggering stagflation dynamics across advanced economies. Energy-intensive manufacturing in Europe and Asia faces margin compression, while emerging markets dependent on fuel subsidies confront fiscal stress.

The IEA noted that “resuming flows through the Strait of Hormuz remains the single most important variable in easing the pressure on energy supplies, prices and the global economy.” Yet the assassination of Iran’s most experienced security leadership has removed the interlocutors capable of negotiating such an arrangement. Second-round talks are under discussion for the week of April 14-20, potentially in Pakistan, but Iranian negotiators now approach the table convinced that Washington uses diplomacy as tactical cover.

What to Watch

Monitor whether second-round Vance-Ghalibaf talks materialise and whether Iranian demands moderate. Current maximalist positions — including war reparations and complete sanctions lift — suggest hardliners view energy supply leverage as durable. Track sanctions waiver renewals past the April 19 expiration; failure to extend General License U would spike prices but reimposing restrictions after temporary relief signals policy incoherence.

Physical crude price spreads over futures indicate structural supply chain disruption beyond Strait closures. Singapore middle distillate prices above $290 per barrel reflect refinery bottlenecks and insurance cost spikes that will persist even if Hormuz flows partially resume. European natural gas markets remain vulnerable to secondary disruptions if conflict expands to Gulf production infrastructure.

Watch IMF growth and inflation forecasts in May for revisions reflecting April supply data. Current models assume conflict resolution by mid-2026; prolonged disruption would require substantial downward growth adjustments and upward inflation revisions, particularly for European economies dependent on Middle Eastern energy imports.

The strategic miscalculation was eliminating Iran’s pragmatic security leadership at the moment diplomatic momentum existed. By killing Khamenei and Larijani, Washington removed the interlocutors capable of managing an off-ramp and installed hardliners whose political survival depends on portraying Western engagement as inherently duplicitous. The result is a regime more willing to absorb economic pain, more sceptical of negotiated settlements, and more confident that energy supply leverage provides durable strategic advantage — precisely the opposite of the decapitation strategy’s intended effect.