In the long arc of Iran's relationship with the outside world — shaped by nearly five decades of sanctions and confrontation — a new ultimatum has arrived, sharper than most. Tehran has warned that any nation joining Washington's sweeping economic isolation campaign will be treated as an enemy, while the Trump administration frames the choice before the world in equally absolute terms: alignment or opposition. The standoff, unfolding six months after US and Israeli airstrikes on Iran, is less a negotiation than a test of whether the international order can hold a coherent position when great p