Secondary sanctions represent the most powerful and controversial element of the US sanctions toolkit. By threatening non-US entities — banks, companies, and individuals anywhere in the world — with exclusion from the US financial system, secondary sanctions extend American economic jurisdiction far beyond its territorial boundaries.
How Secondary Sanctions Work
Primary sanctions prohibit US persons and entities from transacting with designated targets. Secondary sanctions go further, threatening non-US entities that facilitate significant transactions with designated Russian persons or sectors with the loss of access to the US financial system and dollar clearing.
The mechanism’s power derives from the dollar’s role as the world’s primary reserve and transaction currency. Approximately 88% of foreign exchange transactions involve the dollar, and access to dollar clearing through correspondent banking relationships with US financial institutions is essential for most international commercial activity.
Enforcement Actions
The Treasury Department has increasingly targeted third-country entities facilitating sanctions evasion. Banks in Turkey, the UAE, Kazakhstan, and other intermediary jurisdictions have received warnings, compliance guidance, and in some cases formal designations for facilitating transactions with sanctioned Russian entities.
The extraterritorial reach of these measures has produced tangible compliance effects. Major international banks have over-complied with sanctions requirements, implementing blanket restrictions on Russia-related transactions that exceed legal minimums. This “de-risking” behavior has been effective in restricting Russian access to the global financial system but has also produced humanitarian consequences by limiting legitimate transactions.
Assessment
Secondary sanctions are strategically effective but diplomatically costly. Their extraterritorial nature generates resentment among allied nations and accelerates efforts to develop alternative financial infrastructure outside dollar dominance. The long-term strategic calculation must weigh immediate enforcement effectiveness against the gradual erosion of the dollar-denominated financial system that makes secondary sanctions possible.