The principle of "one person, one vote" has guided U.S. democratic practice since the 1960s, however it contains an enduring ambiguity: should representation be based on people or on voters? This poster examines the apportionment debate by comparing representation outcomes under total population counts versus citizen voting-age population. While the U.S. currently relies on total population, a shift to CVAP would disproportionately reduce representation for urban, immigrant-heavy, and minority communities while modestly advantaging Republicans. Situating these findings in the historical context of apportionment controversies, from the Three-Fifths Compromise to contemporary attempts to exclude undocumented residents from the census, this research underscores how a seemingly technical choice about “who counts” carries profound consequences for equality, representation, and the meaning of OPOV in American democracy.