“Equality of representation in the legislature is a first principle of liberty,”John Adams wrote in 1776.

Most Americans would agree. But does “equality of representation” mean equal numbers of people—or equal numbers of voters?

That question is raised by the Court’s decision Monday to hear the case of Evenwel v. Abbott. Evenwel is a challenge to the Texas Legislature’s plan for state Senate districts. The appellants are registered voters from Senate districts that have significantly more eligible voters than some others. The legislature’s districts vary from each other in raw population by less than 10 percent; but in their “citizen voting-age population,” or CVAP, the variation can be as high as 50 percent.  

In their appeal to the Court, the aggrieved voters note that “in Texas, large numbers of non-voters swell the population of certain geographic locations.” The Cato Institute, in a brief urging the Court to take the case, is more specific: Evenwel is about race and national origin. Under the current basis, the Cato brief says, “a relatively small constituency of eligible Hispanic voters ... have their votes ‘over-weighted’ and ‘over-valuated,’ effectively diluting the votes of eligible voters” in districts with fewer Latinos.  Latino voters thus have “disproportionate power.” Though the brief doesn’t mention this, redrawing lines on CVAP would produce districts that are older, whiter, richer, and more likely to vote Republican.

Throughout much of our history, states got to apportion their legislatures any way they wanted. But in a 1964 case called Reynolds v. Sims, the Warren Court proclaimed that “as a basic constitutional standard, the Equal Protection Clause requires that the seats in both houses of a bicameral state legislature must be apportioned on a population basis.” The Court’s explanation, however, created a lasting confusion between population and voters; “an individual’s right to vote for state legislators,” it said, “is unconstitutionally impaired when its weight is in a substantial fashion diluted when compared with votes of citizens living in other parts of the State.” This and later decisions spawned the shorthand phrase, “one person one vote.”

In a 1966 case called Burns v. Richardson, the Court approved a temporary Hawaii districting plan based on the number of eligible voters; the state argued it needed to use that basis, rather than population, because of the large number of military personnel moving in and out of the state. Justice William Brennan’s majority opinion approved Hawaii’s temporary plan “only because” it “produced a distribution of legislators not substantially different from that which would have resulted from the use of a permissible population basis.”

Since then, the Court has formally left the population-basis decision to each individual state.  In 2001, the Court denied review in a case presenting this issue. Justice Clarence Thomas dissented from that denial, arguing that the Court should decide the issue rather than leaving it to states.  “The one-person, one-vote principle may, in the end, be of little consequence if we decide that each jurisdiction can choose its own measure of population,” he wrote.

As the Cato brief makes clear, the hidden issue in Evenwel is Section 2 of the Voting Rights Act. It forbids a state from adopting any “standard, practice, or procedure” that offers racial minorities “less opportunity than other members of the electorate to participate in the political process and to elect representatives of their choice.” It’s hard to generalize, but states with large Latino populations use census figures on raw population—including racial makeup—to draw districts, and then look at the voting-age population (including non-citizens) and and CVAP to ensure they are not “diluting” Latino political power.  As Professor Nathaniel Persily of Stanford pointed out in 2010, current census data on citizenship is less reliable than the census’ raw population counts.

A constitutional rule requiring that districts must be drawn on CVAP alone thus would likely lead to fewer districts in which a majority of voters are Latino.

The voters’ argument is mostly based on phrases taken from the Court’s earlier decisions. The text and history of the Constitution itself don’t offer much support for the idea that voters, not population, should be counted as the basis of representation.

In Article I Section 2, the framers provided that seats the U.S. House of Representatives would be awarded to states “according to their respective numbers.” The “numbers” included immigrants, women, children, and other people ineligible to vote—lumped together as “free persons.” There were two exceptions to the rule: “Indians not taxed” (meaning those living under independent tribal governments) were not counted; and “other persons” (meaning slaves) were counted as three-fifths of “free persons.”

After Emancipation, there were no more “other persons.” Section Two of the Fourteenth Amendment, approved in 1868, now provides that apportionment is to be based on ”the whole number of persons in each State, excluding Indians not taxed.” Population, not voting rights, again. (In 1924, Congress granted citizenship to Native people under tribal government; there are no more “Indians not taxed.”)

Voting rights do appear in the Fourteenth Amendment, however. Immediately after the Civil War, Southern states were happy to have representation apportioned on the basis of the whole population of freed slaves, and not just at three-fifths of that sum, because it would have increased their number of House seats and electoral votes. They also planned to keep the franchise all white, thereby inflating the power of white, southern voters. The framers of the Fourteenth Amendment tried to forestall that, without using racial terms, by providing that when the right to vote “is denied to any of the male inhabitants of such State, being twenty–one years of age, and citizens of the United States, or in any way abridged, except for participation in rebellion, or other crime,” the states would lose representation for the entire excluded group.  (That language has never really been tested; by 1870, the Fifteenth Amendment formally barred racial discrimination in voting altogether.)

Taken together, these provisions suggest that the basic constitutional rule of apportionment is, as the Reynolds v. Sims Court said, raw population. The three-fifths clause in 1787 and the “male inhabitants” clause in 1868 are phrased as extraordinary departures from that rule.

These provisions, of course, do not directly govern the issue in Evenwel. They apply to federal apportionment; the districts in this case are state legislative ones.  The relevant constitutional provision, then is, the equal protection clause of the Fourteenth Amendment: “No state shall ... deny to any person within its jurisdiction the equal protection of the laws.” The privileges and immunities clause appears in the same section; it applies to “citizens of the United States”; equal protection, however, explicitly applies to every “person”—white and non-white, immigrant and native-born, citizen and non-citizen.

What right are we talking about? Is it the individual person’s right to representation? In a democratic system, leaders are elected by voters, but once elected, they represent all the people. Those too young to vote, those excluded because of criminal records, and those who are not citizens are “persons” for equal-protection purposes. Is it the individual voter’s right to an equal vote? Then voting-age population or something like it would be the correct basis for apportionment.

It’s not an easy question; but I think the theory, the text, and the history favor raw population.   

The real issue, though, is VRA Section Two. It impels some states with large Latino populations to draw districts that empower Latino voters—so that Latinos will have the “opportunity” to elect candidates of their choice. That requirement was added after congressional hearings in 1982, to provide a remedy to minority voters against voting procedures and districting that had the effect of reducing their influence, whether or not they can prove that the states intended to do so.  As a young lawyer in the Reagan administration, Chief Justice John Roberts expressed his dismay at this “effects test.” In a 2006 case about “vote dilution,” Roberts wrote a separate opinion that said, “It is a sordid business, this divvying us up by race.” This case might offer a chance to reduce Section Two’s impact.

There’s going to be a lot of high-minded rhetoric about Evenwel. The real currency is bare-knuckle politics. That’s not surprising. Take John Adams’s fine words about equality of representation, for example: He was his native Massachusetts, a populous state, had only one vote in the Continental Congress, the same as tiny Delaware. To people in Delaware, “equality” probably meant something quite different.  And ever since Adams’s time, debates about representation have usually been inspired by partisan advantage, not first principles of liberty.