This chapter addresses the permissibility and effectiveness of political whistleblowing in Europe. On permissibility, the academic discourse maintains that political whistleblowing should be justified, albeit under different normative rationales and conditions. The law fails to follow suit. Despite policy advancements for whistleblowing, including for the first time the European Union wide legal standards, protections for political whistleblowing lag behind. Political whistleblowers in Europe may find vindication at the European Court of Human Rights, yet, in practice, they still experience retaliation despite judicial decisions protecting whistleblowers for speaking out in their workplaces. On effectiveness, political whistleblowing depends on the functionality of the rule of law and institutional checks and balances. This chapter shows that political whistleblowing in some European states has contributed to significant reforms in democratic governance; nevertheless, the current weakening of the rule of law makes the practice of political whistleblowing especially vulnerable.