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Introduction to Political Science

9.3 What Is the Difference between Unicameral and Bicameral Systems?

Introduction to Political Science9.3 What Is the Difference between Unicameral and Bicameral Systems?

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Table of contents
  1. Preface
  2. Introduction to Political Science
    1. 1 What Is Politics and What Is Political Science?
      1. Introduction
      2. 1.1 Defining Politics: Who Gets What, When, Where, How, and Why?
      3. 1.2 Public Policy, Public Interest, and Power
      4. 1.3 Political Science: The Systematic Study of Politics
      5. 1.4 Normative Political Science
      6. 1.5 Empirical Political Science
      7. 1.6 Individuals, Groups, Institutions, and International Relations
      8. Summary
      9. Key Terms
      10. Review Questions
      11. Suggested Readings
  3. Individuals
    1. 2 Political Behavior Is Human Behavior
      1. Introduction
      2. 2.1 What Goals Should We Seek in Politics?
      3. 2.2 Why Do Humans Make the Political Choices That They Do?
      4. 2.3 Human Behavior Is Partially Predictable
      5. 2.4 The Importance of Context for Political Decisions
      6. Summary
      7. Key Terms
      8. Review Questions
      9. Suggested Readings
    2. 3 Political Ideology
      1. Introduction
      2. 3.1 The Classical Origins of Western Political Ideologies
      3. 3.2 The Laws of Nature and the Social Contract
      4. 3.3 The Development of Varieties of Liberalism
      5. 3.4 Nationalism, Communism, Fascism, and Authoritarianism
      6. 3.5 Contemporary Democratic Liberalism
      7. 3.6 Contemporary Ideologies Further to the Political Left
      8. 3.7 Contemporary Ideologies Further to the Political Right
      9. 3.8 Political Ideologies That Reject Political Ideology: Scientific Socialism, Burkeanism, and Religious Extremism
      10. Summary
      11. Key Terms
      12. Review Questions
      13. Suggested Readings
    3. 4 Civil Liberties
      1. Introduction
      2. 4.1 The Freedom of the Individual
      3. 4.2 Constitutions and Individual Liberties
      4. 4.3 The Right to Privacy, Self-Determination, and the Freedom of Ideas
      5. 4.4 Freedom of Movement
      6. 4.5 The Rights of the Accused
      7. 4.6 The Right to a Healthy Environment
      8. Summary
      9. Key Terms
      10. Review Questions
      11. Suggested Readings
    4. 5 Political Participation and Public Opinion
      1. Introduction
      2. 5.1 What Is Political Participation?
      3. 5.2 What Limits Voter Participation in the United States?
      4. 5.3 How Do Individuals Participate Other Than Voting?
      5. 5.4 What Is Public Opinion and Where Does It Come From?
      6. 5.5 How Do We Measure Public Opinion?
      7. 5.6 Why Is Public Opinion Important?
      8. Summary
      9. Key Terms
      10. Review Questions
      11. Suggested Readings
  4. Groups
    1. 6 The Fundamentals of Group Political Activity
      1. Introduction
      2. 6.1 Political Socialization: The Ways People Become Political
      3. 6.2 Political Culture: How People Express Their Political Identity
      4. 6.3 Collective Dilemmas: Making Group Decisions
      5. 6.4 Collective Action Problems: The Problem of Incentives
      6. 6.5 Resolving Collective Action Problems
      7. Summary
      8. Key Terms
      9. Review Questions
      10. Suggested Readings
    2. 7 Civil Rights
      1. Introduction
      2. 7.1 Civil Rights and Constitutionalism
      3. 7.2 Political Culture and Majority-Minority Relations
      4. 7.3 Civil Rights Abuses
      5. 7.4 Civil Rights Movements
      6. 7.5 How Do Governments Bring About Civil Rights Change?
      7. Summary
      8. Key Terms
      9. Review Questions
      10. Suggested Readings
    3. 8 Interest Groups, Political Parties, and Elections
      1. Introduction
      2. 8.1 What Is an Interest Group?
      3. 8.2 What Are the Pros and Cons of Interest Groups?
      4. 8.3 Political Parties
      5. 8.4 What Are the Limits of Parties?
      6. 8.5 What Are Elections and Who Participates?
      7. 8.6 How Do People Participate in Elections?
      8. Summary
      9. Key Terms
      10. Review Questions
      11. Suggested Readings
  5. Institutions
    1. 9 Legislatures
      1. Introduction
      2. 9.1 What Do Legislatures Do?
      3. 9.2 What Is the Difference between Parliamentary and Presidential Systems?
      4. 9.3 What Is the Difference between Unicameral and Bicameral Systems?
      5. 9.4 The Decline of Legislative Influence
      6. Summary
      7. Key Terms
      8. Review Questions
      9. Suggested Readings
    2. 10 Executives, Cabinets, and Bureaucracies
      1. Introduction
      2. 10.1 Democracies: Parliamentary, Presidential, and Semi-Presidential Regimes
      3. 10.2 The Executive in Presidential Regimes
      4. 10.3 The Executive in Parliamentary Regimes
      5. 10.4 Advantages, Disadvantages, and Challenges of Presidential and Parliamentary Regimes
      6. 10.5 Semi-Presidential Regimes
      7. 10.6 How Do Cabinets Function in Presidential and Parliamentary Regimes?
      8. 10.7 What Are the Purpose and Function of Bureaucracies?
      9. Summary
      10. Key Terms
      11. Review Questions
      12. Suggested Readings
    3. 11 Courts and Law
      1. Introduction
      2. 11.1 What Is the Judiciary?
      3. 11.2 How Does the Judiciary Take Action?
      4. 11.3 Types of Legal Systems around the World
      5. 11.4 Criminal versus Civil Laws
      6. 11.5 Due Process and Judicial Fairness
      7. 11.6 Judicial Review versus Executive Sovereignty
      8. Summary
      9. Key Terms
      10. Review Questions
      11. Suggested Readings
    4. 12 The Media
      1. Introduction
      2. 12.1 The Media as a Political Institution: Why Does It Matter?
      3. 12.2 Types of Media and the Changing Media Landscape
      4. 12.3 How Do Media and Elections Interact?
      5. 12.4 The Internet and Social Media
      6. 12.5 Declining Global Trust in the Media
      7. Summary
      8. Key Terms
      9. Review Questions
      10. Suggested Readings
  6. States and International Relations
    1. 13 Governing Regimes
      1. Introduction
      2. 13.1 Contemporary Government Regimes: Power, Legitimacy, and Authority
      3. 13.2 Categorizing Contemporary Regimes
      4. 13.3 Recent Trends: Illiberal Representative Regimes
      5. Summary
      6. Key Terms
      7. Review Questions
      8. Suggested Readings
    2. 14 International Relations
      1. Introduction
      2. 14.1 What Is Power, and How Do We Measure It?
      3. 14.2 Understanding the Different Types of Actors in the International System
      4. 14.3 Sovereignty and Anarchy
      5. 14.4 Using Levels of Analysis to Understand Conflict
      6. 14.5 The Realist Worldview
      7. 14.6 The Liberal and Social Worldview
      8. 14.7 Critical Worldviews
      9. Summary
      10. Key Terms
      11. Review Questions
      12. Suggested Readings
    3. 15 International Law and International Organizations
      1. Introduction
      2. 15.1 The Problem of Global Governance
      3. 15.2 International Law
      4. 15.3 The United Nations and Global Intergovernmental Organizations (IGOs)
      5. 15.4 How Do Regional IGOs Contribute to Global Governance?
      6. 15.5 Non-state Actors: Nongovernmental Organizations (NGOs)
      7. 15.6 Non-state Actors beyond NGOs
      8. Summary
      9. Key Terms
      10. Review Questions
      11. Suggested Readings
    4. 16 International Political Economy
      1. Introduction
      2. 16.1 The Origins of International Political Economy
      3. 16.2 The Advent of the Liberal Economy
      4. 16.3 The Bretton Woods Institutions
      5. 16.4 The Post–Cold War Period and Modernization Theory
      6. 16.5 From the 1990s to the 2020s: Current Issues in IPE
      7. 16.6 Considering Poverty, Inequality, and the Environmental Crisis
      8. Summary
      9. Key Terms
      10. Review Questions
      11. Suggested Readings
  7. References
  8. Index

Learning Outcomes

By the end of this section, you will be able to:

  • Define unicameral and bicameral legislature.
  • Outline which types of legislative systems exist in different parts of the world.
  • Analyze the relative advantages and disadvantages of each type of legislative system.

One key structural component of legislatures is the number of chambers that they have. The two most common options for chamber structure are unicameral and bicameral. A unicameral legislature has only one chamber, or body, that makes decisions. A bicameral legislature has two chambers, often with different procedures and powers, that ultimately must work together to make policy and exercise other legislative powers and responsibilities.

Strengths and Weaknesses of a Unicameral Legislature

One of the main strengths of unicameral legislatures is that they create a more efficient legislative process. In a unicameral legislature, bills only need to go before and be debated by one set of decision makers, whereas in a bicameral legislature, both chambers must debate and approve bills in order for them to have a chance of becoming laws. This legislative efficiency is particularly valued in more homogenous societies, where having venues for different voices and perspectives is not seen as particularly important. In these societies, political parties are considered sufficient to protect diverse interests.

Unicameral systems do not lend themselves to oversight and checks on the power of the legislature. In bicameral systems, the need to pass legislation through another chamber is a natural “veto point”; if there is support for legislation in one chamber but not the other, that may reflect broad concerns of a segment of the public, so the public’s preferences are better served when both chambers weigh in and consider a piece of legislation. The lack of a natural “veto point” is particularly apparent in unicameral parliamentary systems, where a prime minister with a strong governing majority faces almost no constraints from either a separate chamber or an effective minority opposition.

Strengths and Weaknesses of a Bicameral Legislature

Bicameral systems make up approximately one-half of legislatures around the world. Bicameralism is largely thought to allow the structures of a political system to reflect different voices and priorities. In bicameral systems, there is often a lower chamber, more closely associated with the perspective of the people, and an upper chamber, which might reflect different territories or classes.52 For example, in the German parliamentary system, the lower chamber, the Bundestag, is directly elected by the public, while the upper chamber, the Bundesrat, is supposed to represent the 16 Länder, or states. While each state has between three and six votes on legislation, all of a state’s votes in the Bundesrat must be cast as a bloc, either for or against a piece of legislation.53 The idea is that the vote should represent the state’s interests, not the interests of the individuals representing the state. The two chambers create a system of checks and balances within the legislative branch so that any legislation that can survive the legislative branch process is much more likely to succeed.

Young adult student journalists wearing lanyards sit facing forward in tiered rows of two-person desks.
Figure 9.13 Student journalists participate in a 2017 celebration of youth journalism taking place on the floor of the German Bundesrat. Note how the names of the Länder are affixed to the desks, highlighting the importance of representing a particular region. (credit: “Preisverleihung - SZWdL17” by Jugendpresse Deutschland/Timon Suhk/Flickr, CC BY 2.0)

There are important weaknesses to bicameral systems. First, the legislative process is inefficient. After a bill has been investigated, debated, and voted on in one chamber, it must go to a second chamber and complete the whole process again. This can both significantly extend the time it takes for a piece of legislation to pass and dramatically raise the odds that a piece of legislation will die before it gets to a vote, as at every stage along the way there are two sets of decision makers who can choose not to proceed with a piece of legislation. This phenomenon played a significant role in preventing comprehensive immigration reform in the United States in the first two decades of the 21st century. One nuance of the American legislative process is that bills that haven’t passed both chambers of Congress expire at the end of each two-year session. Although a number of different pieces of immigration legislation were introduced between 2000 and 2020, and some passed either the House or the Senate, no comprehensive immigration legislation was signed into law.54 Additionally, both chambers must pass the exact same text of legislation. As many systems allow both chambers to amend legislation, a piece of legislation can bounce back and forth between the two chambers until they can agree on a final version. That can also add significant time and inefficiencies to the legislative process.

Another weakness of bicameralism is that it can suffer from gridlock when different parties hold the majority in each chamber, particularly when the two parties in charge have significant policy and ideological disagreements.

The strengths and weaknesses of bicameralism are two sides of the same coin. A system that, by design, allows for more voices can become a system where nothing can happen, as disagreement in the legislature can cause everything to come to a screeching halt.

Show Me the Data

Frequency of Unicameral and Bicameral Legislatures around the World

A world map codes countries according to whether they have bicameral or unicameral legislatures, some variant, or no legislature at all.
Figure 9.14 Approximately half of the countries around the world have bicameral legislatures (in green), while the other half have unicameral legislatures (in blue). A few countries, for example China and Iran, have unicameral legislatures with separate advisory bodies (brown), and a couple others have no legislature at all (red). (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license)

A quick look around the world shows some interesting patterns. Many large countries have a bicameral legislative system. In part, this reflects the influence that the United States and European countries have around the globe. But a significant number of countries, including countries in western and southern Africa, Central America, the Middle East, and northern Europe, as well as many island nations, have unicameral legislatures. What characteristics do you think influence countries to adopt one structure of legislature versus the other?

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