Money is the root of all politics.
Politics is split into disparate causes. Environmentalism, class equity, social justice, feminism, gun control, abortion, immigration, and many other causes divide potentially larger political groups into smaller, more niche groups. These niche groups may have the passion to focus on a particular cause. Unfortunately, they also lack the capital or manpower to actually achieve their goals strategically.
Furthermore, the success of these causes are hindered for one reason: people with money oppose these causes.
Therefore, there are two major problems with our current political system: one, political groups are too divided; and two, corporate and upper-class money prevents politicians from considering the causes of these groups because such politicians need corporate and upper-class money to compete in elections.