5 ideas
Sanctions work mainly when the goal is narrow and concrete, such as releasing a prisoner or halting a specific policy. They almost never produce regime change or force an adversary to give up core security interests. When policymakers attach grand objectives to economic pressure, failure is close to built in, while the costs to the target's population and to the sender keep growing.
Demarais identifies four factors that tend to make sanctions more effective: the target depends economically on the sender, often as a friend or ally rather than a rival; the sender builds a broad multilateral coalition; the demand is limited and clearly defined; and the measures are short in duration rather than drawn out. These raise the odds of success rather than acting as strict requirements, and where they are missing the target has more room to absorb, substitute, or wait out the pressure.
Every use of dollar-based financial sanctions shows other governments the risk of depending on US-controlled payment channels, and so creates demand for alternatives. China's CIPS payment system, digital yuan experiments, and trade settled in local currencies are best read as a defensive response to sanctions. Measured this way, the long-run cost of a sanction includes the permanent erosion of the dominance that made it powerful in the first place.
Extraterritorial US sanctions, such as the Iran measures reimposed after 2018, penalise European and Asian companies for trading with third countries, and this has fed allied resentment and a push for financial autonomy from Washington. Europe answered with the INSTEX trade channel and its blocking statute, which did not work well but signalled that allies see US financial reach as a challenge to their sovereignty.
Sanctions rules are complex and violations carry very large fines, so banks and firms often cut off entire countries rather than just the listed targets. This is called de-risking or overcompliance. As a result, food, medicine, and humanitarian payments get blocked even when they are formally exempt. Ordinary people absorb much of the cost, while elites find workarounds.