On a Friday in early autumn, the United States extended its financial pressure campaign against Iran by sanctioning a Turkish bank and two of its subsidiaries — not for what they are, but for what they enabled. The action reflects a maturing doctrine in American foreign policy: that the architecture of global finance can itself become an instrument of geopolitical will, and that any institution touching Iranian transactions risks being severed from the dollar-denominated world. In targeting a NATO ally's bank, Washington signals that strategic partnerships offer no immunity from the logic of e