“Plumbing” is the metaphor of choice for describing how sanctions work. Sanctions are intended to stop the flow of money to the targeted government; reserves are frozen, trade is blocked, export revenues dry up, and government budgets are drained. Even the evasion of sanctions is discussed in hydraulic terms. When asked about the circumvention of sanctions against Russia earlier this year, Linda Thomas-Greenfield, the United States representative to the United Nations, replied that the Biden administration was “looking at that leakage.” “Every place we see leakage,” she said, “we’re stopping it up.” (On some occasions, the image becomes literal: European Union export controls ban the export of “bidets, toilets, cisterns, and similar plumbing fixtures” to Russia.)

The plumbing metaphor reflects a highly mechanical and often misleading understanding of economic coercion. In a recent statement, Treasury Secretary Janet Yellen acknowledged that while US sanctions on Iran “have created a real economic crisis in the country,” the measures have not “forced a change in behavior.” Yellen’s admission speaks to a broader and growing concern over the efficacy of sanctions. Even measures that demonstrably hurt the targeted economy — by blocking flows and draining budgets — may not lead to a change in the behaviors that spurred their imposition. In sanctions policy, the targeted economy is treated as a static system — a machine. But to really understand sanctions, we must investigate how actors in a complex system relate to one another, and how changes in those relationships can change the system itself. The distributional effects of sanctions matter most.

Iran has been subjected to the world’s most extensive sanctions program for the better part of the last decade. Its experience is instructive: while sanctions were intended to target the country’s elite, the wealthiest households have fared far better than the poorest during the period. In fact, it appears that sanctions rigged the game, enabling a structural transformation of the economy that helped Iran’s richest households take a greater share of the nation’s wealth.