Supranational issues require supranational bodies. There is a good article in the FT today about how the UK leaving the EU, and of course cross border threats such as the pandemic for example, have just pushed EU countries into closer cooperation across the board. Yes, sometimes a case can be made for overreach, an intrusion too far into national competencies, but the ECHR hardly falls into that category. The UK's gradual descent into illiberalism and its constant eroding of its own citizen's rights will not be corrected by this government. Would you trust them to enforce those same ECHR rights? fudge no. They will not police themselves, just you, unfortunately.