Iran’s Supreme Leader Ayatollah Ali Khamenei told a crowd in Tehran on 1 February that if the United States were to “start a war” it would quickly escalate into a “full-scale regional war,” a remark carried by state and Iranian media. Speaking to representatives from across Iranian society, Khamenei framed the warning as both a refusal to be intimidated by U.S. military posturing and a promise that Iran would respond firmly to any aggression.
The comments come against a backdrop of persistent tensions between Washington and Tehran that have featured sanctions, a U.S. withdrawal from the 2015 nuclear agreement, lethal strikes such as the 2020 killing of Qassem Soleimani, and repeated maritime and proxy confrontations across the Gulf and Levant. Khamenei explicitly referenced American rhetoric that “all options are on the table” and recent U.S. declarations about carrier deployments, dismissing such threats as unlikely to cow the Iranian public or leadership.
Domestically, the speech serves several purposes. It reassures a population accustomed to intermittent crisis and economic pressure that the regime will defend national honour, while reinforcing Khamenei’s role as the ultimate arbiter of security policy. The statement also signals to Iran’s regional partners and proxies that Tehran retains appetite and capacity to escalate in defence of its interests, a useful deterrent posture that simultaneously lowers the bar for calibrated retaliatory responses.
Regionally, the stakes are high. A conflict between the U.S. and Iran would not be confined to bilateral strikes; it could involve Iraqi militias, Lebanese Hezbollah, Syrian battlefields and Yemen’s Houthis, and threaten choke points such as the Strait of Hormuz. That dynamic raises the prospect of disruptions to energy supplies and commercial shipping, and puts neighbouring states — particularly U.S. partners in the Gulf and Israel — at acute risk of being drawn into hostilities or facing spillover attacks.
From the U.S. perspective, Khamenei’s warning complicates any calculus about the utility of force. Washington must weigh the limited tactical gains of strikes against the strategic risk of a broader conflagration it may not control, and against political constraints among allies wary of escalation. The result is a narrow window for coercive options: threats can be reinforced by sanctions, diplomatic isolation and targeted strikes, but these measures carry the perpetual danger of miscalculation between Tehran’s proxies and U.S. forces or partners.
The immediate implication is a mutual deterrence in which rhetoric increases but direct confrontation remains a dangerous, costly option for both sides. International actors with influence in the region — from European capitals to Moscow and Beijing — have a clear interest in preventing missteps that could spark wider warfare. The moment underscores the continuing fragility of Middle East security and the premium on crisis-management channels, even between adversaries.