Final answer:
Apportionment is the allocation of congressional seats among states post-census, involving redistricting to ensure equal populations while preventing gerrymandering that can skew representation.
Step-by-step explanation:
The process occurring after every decennial census that allocates congressional seats among the 50 states is called apportionment. This process involves the redistricting of legislative district boundaries to maintain relatively equal population numbers in each district and adhere to the Voting Rights Act, which prohibits drawing district lines that diminish the voting power of minorities.
However, this process can be subject to gerrymandering, where district lines are manipulated to favor a particular political party or group, potentially affecting election outcomes and representation for the next decade.