The joint American and Israeli attack on Iran, launched over the weekend with the declared objective of regime change in Tehran, is aimed squarely at undoing the 1979 Islamic Revolution. That revolution created a new model of religious politics, transformed the regional balance of power, upended global energy flows, and altered the very geometry of great-power relations.For India, the 1979 revolution — along with the Soviet intervention in Afghanistan — reshaped its regional political, economic, energy, and security landscape. As the future of the Islamic Republic hangs in the balance, New Delhi must factor the potential fallout into its own strategic calculus. India has limited capacity to influence the outcome of the conflict, but it will have to prepare for the cascading effects of the confrontation between the US-Israel alliance and Iran.The killing of Ayatollah Ali Khamenei, Iran’s Supreme Leader, raises two central questions: the resilience of the Islamic state and the prospects of a new, US-backed or US-friendly government in Tehran. Whether the Islamic Republic collapses, fractures, or adapts will shape regional and global politics for years.Also Read | After Khamenei: Who is Alireza Arafi, the ‘seasoned cleric’ now tasked with temporarily leading Iran?The regime’s harsh internal repression over the decades — and the deep popular revulsion against it — are no secret. Iran has seen major protest movements roughly every five years since the turn of the century, including the large demonstrations as recently as December and January. Yet each uprising was crushed by the entrenched security apparatus of the Islamic state.But that history does not mean opponents of the regime can now simply walk into the streets and take over. The next phase is likely to witness a mobilisation of the Islamic Republic’s supporters even as its detractors push for transformational change. For now, however, the means of violence and coercion remain concentrated in the hands of the old order. How far external intervention can weaken that monopoly will determine the political trajectory in Tehran.At the heart of the crisis lies the unique structure of clerical rule created by the 1979 revolution. Power is vested in a Supreme Leader — a cleric who exercises full religious and political authority. Many Iranian religious and political figures have contested this system of clerical rule, but Khamenei suppressed all challenges and consolidated complete control. The key question is whether his successor can hold this edifice together.History suggests that even rigid political systems change eventually, though not necessarily peacefully. What comes next depends on whether the Islamic state can maintain cohesion after Khamenei — and whether the US and Israel can effectively support domestic forces seeking to remake the state.Story continues below this adAlso Read | Where does Iran — and the world — go from Khamenei death? All you need to knowThe Islamic Revolution in Iran was more than a national project; it sought to export its revolutionary Islamic ideology across the Middle East. All major revolutions proclaim universalism, but most eventually prioritise national interest over ideology. The “country” rather than the “cause” tends to dominate over time. But Iran was an exception.Tehran has sought to sustain a permanent revolution by championing the Palestinian cause more aggressively than the Arab states and positioning itself as a radical challenger to Israel and the US.This posture alarmed not only Washington and Tel Aviv, but also conservative Arab rulers threatened by the revolutionary republicanism of Tehran and by its mobilisation of Shia minorities across the region. The fact that few Middle Eastern governments are willing to stand with Iran today highlights the isolation of the Islamic Republic.The Gulf Arab states, which initially proclaimed neutrality in the US-Israeli confrontation with Iran, have now closed ranks against Tehran as Iranian missiles target both American bases and Gulf civilian infrastructure.Story continues below this adMuch has been said about the “Arab street” favouring Iran, but in the brutal world of regional statecraft, Arab public sentiment has rarely shaped strategic outcomes. The decisive arena remains the Iranian street — especially urban populations hoping to loosen the regime’s chokehold and push for a more open, if not fully secular, future.The regional reverberations are equally significant. In the 1980s, under pressure from Iran’s revolutionary activism, Arab governments accommodated radical forces at home and encouraged their projection abroad — a dynamic that fuelled the explosion of Islamist radicalism across the region and beyond.Could a more liberal Iran push back against the Islamist politics around the world and strike a blow for separating religion from politics?As Iran hardened its resistance posture and survived expansive sanctions and American hostility, its threat perception among Arab rulers only deepened. This, in turn, strengthened incentives for reconciliation with Israel and for closer security cooperation with the US.Story continues below this adThe 1979 revolution also triggered the 1980 oil shock and reshaped global energy markets. Today’s crisis is once again tied to oil. Iran holds some of the world’s largest hydrocarbon reserves, and the widening conflict in the Strait of Hormuz is already driving prices upward. If a new regime emerges in Tehran — one less confrontational with the world — the lifting of sanctions could bring Iranian oil back into global markets, easing energy prices.Such an outcome would certainly be welcome in Delhi. The natural synergies between India and Iran have not come into play all these decades, because of Iran’s confrontation with the US, Israel and the Gulf Arabs. An Iran at peace with the world, would also be a great partner for India.Before 1979, Iran was one of Washington’s closest allies in the Middle East, alongside Saudi Arabia. If the Islamic Republic is overthrown and a successor regime aligns more closely with the US and Israel, the region’s geopolitics will undergo a profound reordering.Beyond the Middle East, Tehran’s fate will shape wider great-power competition. As it confronted the US, the Islamic Republic became an important partner for Russia and China — economically, strategically, and institutionally.Story continues below this adIran became part of BRICS Plus and joined the Shanghai Cooperation Organisation, embedding itself in a Eurasian framework that pushed back against Western influence. A regime change in Tehran would, therefore, represent a major setback for Moscow and Beijing and weaken their position in the contest with Washington.Few revolutions in the modern era have been as consequential as the 1979 Islamic upheaval in Iran. The effort now underway to overturn it will be equally consequential — not just for the Middle East, but for the wider world, including India. The coming weeks may well redraw political boundaries, reconfigure energy markets, and alter the logic of great-power alignments.For New Delhi, the challenge is not about influencing these developments, but preparing for their impact. Whatever emerges in Tehran will cast a long shadow across the region India inhabits — and the world it must navigate.(C. Raja Mohan is a contributing editor on international affairs for The Indian Express. He is also associated with the Jindal Global University and the Council on Strategic and Defence Studies, Delhi.)