Science and policy perform complementary tasks. Without any understanding of how the real world operates, it would be rather difficult to influence it. Similarly, it seems less relevant to understand what is going on, if these insights are not used for better policies. Scientists and policy makers therefore need to make efforts to understand each other.
Policy makers can learn from structuring their thinking and ensuring its consistency. Scientists can learn from incorporating the flexibility and practical relevance that is needed for solving real world problems under political constraints. I therefore do not believe in a model in which universities focus exclusively on science while policy making institutions abstain from any role in scientific research.