With the Supreme Court’s decision to hear Evenwel today on whether it is permissible to include non-voters (including non-citizens) in drawing legislative districts, it is worth remembering what the Supreme Court said about this in the 1966 case, Burns v. Richardson, which I had thought settled it as the state’s choice (my emphasis below):

The dispute over use of distribution according to registered voters as a basis for Hawaiian apportionment arises because of the sizable differences in results produced by that distribution in contrast to that produced by the distribution according to the State’s total population, as measured by the federal census figures. In 1960 Oahu’s share of Hawaii’s total population was 79%. Its share of persons actually registered was 73%. On the basis of total population, Oahu would be assigned 40 members of the 51-member house of representatives; on the basis of registered voters it would be entitled to 37 representatives.^[17] Probably because of uneven distribution of military residents—largely unregistered—the differences among various districts on Oahu are even more striking. For example, on a total population basis, Oahu’s ninth and tenth representative districts would be entitled to 11 representatives, and the fifteenth and sixteenth representative districts would be entitled to eight. On a registered 91*91 voter basis, however, the ninth and tenth districts claim only six representatives and the fifteenth and sixteenth districts are entitled to 10.^[18]

The holding in Reynolds v. Sims, as we characterized it in the other cases decided on the same day, is that “both houses of a bicameral state legislature must be apportioned substantially on a population basis.”^[19] We start with the proposition that the Equal Protection Clause does not require the States to use total population figures derived from the federal census as the standard by which this substantial population equivalency is to be measured. Although total population figures were in fact the basis of comparison in that case and most of the others decided that day, our discussion carefully left open the question what population was being referred to. At several points, we discussed substantial equivalence in terms of voter population or citizen population, making no distinction between the acceptability of such a test and a test based on total population.^[20] Indeed, inWMCA, Inc. v. Lomenzo, 377 U. S. 633, decided the same day, we treated an apportionment based upon United States citizen population as presenting problems 92*92 no different from apportionments using a total population measure. Neither in Reynolds v. Sims nor in any other decision has this Court suggested that the States are required to include aliens, transients, short-term or temporary residents, or persons denied the vote for conviction of crime, in the apportionment base by which their legislators are distributed and against which compliance with the Equal Protection Clause is to be measured.^[21] The decision to include or exclude any such group involves choices about the nature of representation with which we have been shown no constitutionally founded reason to interfere. Unless a choice is one the Constitution forbids, cf., e. g., Carrington v. Rash, 380 U. S. 89,the resulting apportionment base offends no constitutional bar, and compliance with the rule established in Reynolds v. Sims is to be measured thereby.

Use of a registered voter or actual voter basis presents an additional problem. Such a basis depends not only upon criteria such as govern state citizenship, but also upon the extent of political activity of those eligible to register and vote. Each is thus susceptible to improper influences by which those in political power might be able to perpetuate underrepresentation of groups constitutionally entitled to participate in the electoral process, 93*93 or perpetuate a “ghost of prior malapportionment.”^[22] Moreover, “fluctuations in the number of registered voters in a given election may be sudden and substantial, caused by such fortuitous factors as a peculiarly controversial election issue, a particularly popular candidate, or even weather conditions.” Ellis v. Mayor & City Council of Baltimore,352 F. 2d 123, 130 (C. A. 4th Cir. 1965).^[23] Such effects must be particularly a matter of concern where, as in the case of Hawaii apportionment, registration figures derived from a single election are made controlling for as long as 10 years. In view of these considerations, we hold that the present apportionment satisfies the Equal Protection Clause only because on this record it was found to have produced a distribution of legislators not substantially different from that which would have resulted from the use of a permissible population basis.

As the District Court noted, the 1950 constitutional convention discussed three possible measures, total population, state citizen population, and number of registered voters, in considering how the State House of Representatives should be apportioned. Apportionment under the Organic Act had been on the basis of citizen population; this had proved difficult to administer because statistics were not readily available. Total population was disfavored because the census tracts, by which it is determined and reported, did not necessarily comport with traditional local boundaries. Registered voters was chosen as a reasonable approximation of both citizen and total population—readily determinable, conveniently 94*94 broken down by election district, and a measure which, as against total population, somewhat favored the other islands over Oahu. It is fair to say that the convention report reflected that citizen population as much as total population was the basis against which a registered voters standard was compared.

Hawaii’s special population problems might well have led it to conclude that state citizen population rather than total population should be the basis for comparison. The District Court referred to the continuing presence in Hawaii of large numbers of the military: “Hawaii has become the United States’ military bastion for the entire Pacific and the military population in the State fluctuates violently as the Asiatic spots of trouble arise and disappear. If total population were to be the only acceptable criterion upon which legislative representation could be based, in Hawaii, grossly absurd and disastrous results would flow . . . .” 238 F. Supp., at 474.^[24] Similarly, the court referred to the distortion in census figures attributable to “the large number of tourists who continually flow in and out of the State and who . . . for census purposes are initially at least, counted as part of Hawaii’s census population . . . .” Id., at 475. (Footnote omitted.) Both the tourists and the military tend to be highly concentrated on Oahu and, indeed, are largely confined to particular regions of that island. Total population figures may thus constitute a substantially distorted reflection of the distribution of state citizenry. If so, a finding that registered voters distribution does 95*95 not approximate total population distribution is insufficient to establish constitutional deficiency. It is enough if it appears that the distribution of registered voters approximates distribution of state citizens or another permissible population base.

Because state citizen population figures are hard to obtain or extrapolate, a comparison of the results which would be obtained by use of such figures with the results obtained by using registered voter figures is difficult. But the District Court found that military population of Oahu, and its distribution over that island, was sufficient to explain the already noted differences between total population and registered voters apportionments, both as among Hawaii’s four counties and as among Oahu’s representative districts. The District Court noted “that there is nothing in the State Constitution or the Hawaii statutes which per se excludes members of the armed forces from establishing their residence in Hawaii and thereafter becoming eligible to vote. This court finds no scheme in Hawaii’s Constitution or in the statutes implementing the exercise of franchise which is aimed at disenfranchising the military or any other group of citizens.” 238 F. Supp., at 475. No issue was raised in the proceedings before it that military men had been excluded improperly from the apportionment base.^[25] 96*96 Moreover, the District Court stressed that Hawaii’s Constitution and laws actively encourage voter registration. A high proportion of the possible voting population is registered,^[26]and “strong drives to bring out the vote have resulted in a vote of from 88 to 93.6% of all registered voters during the elections of 1958, 1959, 1960 and 1962.” Id., at 476 (footnote omitted). In these circumstances, we find no demonstrated error in the District Court’s conclusion that the apportionment achieved by use of a registered voters basis substantially approximated that which would have appeared had state citizen population been the guide.

We are not to be understood as deciding that the validity of the registered voters basis as a measure has been established for all time or circumstances, in Hawaii or elsewhere. The District Court was careful to disclaim any holding that it was a “perfect basis.” We agree. It may well be that reapportionment more frequently than every 10 years, perhaps every four or eight years, would better avoid the hazards of its use. Use of presidential election year figures might both assure a high level of participation and reduce the likelihood that varying degrees of local interest in the outcome of the election would produce different patterns of political activity over 97*97 the State. Other measures, such as a system of permanent personal registration, might also contribute to the stability and accuracy of the registered voters figure as an apportionment basis. Future litigation may reveal infirmities, temporary or permanent, not established by the present record.^[27] We hold that, with a view to its interim use, Hawaii’s registered voter basis does not on this record fall short of constitutional standards.