Final answer:
In apportionment of Senate and House districts, each district must be composed of contiguous areas with roughly equal population size, following the one-person-one-vote principle. This ensures equal representation and affects the number of presidential electors. Apportionment is based on U.S. Census data and is updated every ten years.
Step-by-step explanation:
With respect to apportionment of Senate and House districts, districts must be composed of contiguous areas and roughly equal population size to ensure that representation is fair and that every person's vote carries approximately the same weight. This is in accordance with the one-person-one-vote principle established by the Supreme Court in Reynolds v. Simms (1964), which seeks to prevent malapportionment. Congressional apportionment today uses a mathematical formula to allocate seats in the House of Representatives based on U.S. Census Bureau population data, which is updated every ten years.
District boundaries are redrawn after each decennial U.S. Census to reflect population changes and to maintain equal representation. This process is crucial because it ensures that districts represents the people equally based on population. Each state receives a number of seats in the House proportionate to its population, while there are always two senators per state, regardless of its size.
Furthermore, this apportionment influences the number of electors for the election of the President and Vice President. These electors are equal to the number of senators and representatives to which the District would be entitled if it were a state.