Final answer:
The government action that defines the apportionment of seats in the House of Representatives is based on the Constitution's mandates and subsequent legislation, which employs a mathematical formula every ten years following the census to ensure proportional representation based on population data.
Step-by-step explanation:
Government Action Defining House of Representatives Apportionment
The apportionment of seats in the House of Representatives is a key government action and is defined primarily by the equal proportions method. This process takes place every ten years, aligned with the U.S. Census Bureau population data collection as mandated by the Constitution. Initially, the House expanded with the growing population of the United States until it was capped at 435 members after the 1910 census. Despite challenges, such as the deadlock in 1920, the permanent cap was established with the passage of legislation in 1929.
Article I, Section 2 of the Constitution stipulates that representation is to be proportionate to state populations, with the intention that larger populations would garner more representatives while ensuring that every state has at least one representative. This section also historically included the three-fifths compromise regarding the apportionment of slaves. The concept of apportionment is further refined by various amendments and clauses, including considerations for the representative approach of the federal district.
Furthermore, some states implemented their methods to ascertain equal representation, with varying levels of property qualifications and adjustments based on state-specific censuses. Nonetheless, the overarching principle reflects the desire to have an equitable representation of the populace in the legislative process.