The main purpose of politicians is to represent their constituents. However, politicians are statistically prone to tilting legislation towards the upper class thereby under-representing the lower class. Furthermore, these disparities are stable across time. Nevertheless, when studies control for the fact that the upper class is more likely to vote, give financial contributions, and contact their representatives this effect is still seen. Why? It is because most politicians are upper class, which causes them to vote the way upper class citizens do, even if it does not represent the majority of their constituents.