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Why do legislatures use bicameral systems with two houses?
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Legislation
Former U.S. president Harry S. Truman (right) looking on as U.S. Pres. Lyndon B. Johnson signs the Medicare bill at the Harry S. Truman Library and Museum in Independence, Missouri, July 30, 1965.
Legislatures utilize a bicameral system—a structure comprising two houses—primarily to apply the principle of checks and balances to the lawmaking process.1
This dual-chamber design serves several key purposes:
- Deliberation and Stability: It is intended to secure thorough deliberation and prevent the passage of hasty or harsh legislation.1
- Representation of Interests: Historically, two houses allowed for the representation of distinct groups, such as the nobility versus commoners, or the interests of a central government versus those of local provinces or states. In federal systems, the second chamber often ensures that smaller states maintain influence alongside larger ones.1
- Limiting Power: Some framers of government, including the U.S. Founding Fathers, viewed a second house as a way to temper the influence of popular opinion and provide a check on direct democracy.12
While bicameralism remains common in federal governments, many nonfederal states have shifted toward unicameral systems in the post-World War II era to streamline legislative processes.1