The first reason is that the Framers feared mob rule—they did not think that the American people could govern themselves directly, as they would be swayed by their passions and would only put the most popular people in charge who would endorse their own selfish interests and not look at the long-term needs of the state. The Framers decided that the Senate should have important jobs such as constructing legislation and treaty ratification. However, there was still the fear that even a local legislative body could become unresponsive and disregard the needs of the people, so the Framers allowed the House of Representatives to originate all taxation bills.

Secondly, the American bicameral legislative system springs from Roger Sherman's Great Compromise which allowed the small states and large states to get together under one government. Representation in the Senate is a flat rate—every state gets two senators, regardless of size. Representation in the House is based on population, which gives the more populous states an advantage. This was considered the only fair way to get the states together so that the large states maintained their voice and the small states could have their wishes known as well.