Your friend who's obsessed with watching Congressional debates and listening to experts discuss the bills being voted on in the Senate has a keen interest in politics, or the details of governing or managing a state or a country.
While politics usually refers to the government of a city, state, or country — or the relationship between countries — it can also be used to talk about the way people use their positions in a company or organization to gain power or authority. This is often called office politics. Another similar phrase is playing politics, which means doing something in order to become more powerful rather than doing what's right.