The European Union last week acquired a legal power it has never held before: the ability to ban an entire country’s cryptocurrency sector from transacting with European operators — not just individual exchanges, not just specific tokens, but every crypto-asset service operating within a jurisdiction Brussels decides is enabling Russian sanctions evasion.

The authority, written into a new annex (Annex LVII) to EU Regulation 833/2014 as part of the bloc’s 21st Russia sanctions package adopted on July 23, was built specifically because the old approach — designating platforms one at a time — demonstrably failed. Blockchain analytics firms documented how each exchange closure produced a successor, each successor produced a workaround,…