The matter is a little more complex than this, given the EU itself is a signatory to ECHR, so indirectly via the ECJ and so forth decisions via the ECHR can aff

The matter is a little more complex than this, given the EU itself is a signatory to ECHR, so indirectly via the ECJ and so forth decisions via the ECHR can affect any EU member. Historically the ECHR has been a hugely respected Court, the shame alone of an adverse decision against a State has often been more than enough to prompt action. Most EU states have domestic legislation forcing their courts to interpret domestic statute in a manner compatible with the ECHR. Some go even further. Scotland's parliament, for example, is entirely unable to legislate in a manner incompatible with the ECHR. In today's world, with its crumbling institutions, who knows if the 'shame' effect still means what it once did.