Opinion of Advocate General Szpunar delivered on 9 December 2021.#European Commission v Kingdom of Spain.#Failure of a Member State to fulfil obligations – Liability of Member States for harm caused to individuals by infringements of EU law – Infringement of EU law attributable to the national legislature – Infringement of the Constitution of a Member State attributable to the national legislature – Principles of equivalence and effectiveness.#Case C-278/20.