This paper describes OpinioNetIt, a structured, faceted, knowledge-base of opinions, and its use in political opinions analysis. OpinioNetIt consists of information about people, topics and opinions in the form of person, opinion, topic triples, indicating the opinion of a person on a topic. Our specific focus has been on acquiring opinions held by various stakeholders on politically controversial topics. Our system can be used for various kinds of analysis, including, heat maps showing political bias, flip-flopping politicians, dissenters, etc. In this paper, we describe the architecture of our system, and how it can be used to address these various use-cases.