Post-truth politics is when politicians and other leaders make decisions and statements that aren't true or not supported by facts. Instead, they make decisions and statements based on their feelings and beliefs. This can be seen with leaders who are making decisions on immigration or climate change, for example. They may say that immigration is bad and climate change isn't real even though there's plenty of evidence that both are true. Post-truth politics can be dangerous because it means leaders are not making decisions based on facts, which can lead to bad policies and outcomes.