A. J. Pate, who has been involved in redistricting efforts for decades, has written this guest post on the question whether zero deviation in population for congressional districts is constitutionally compelled:

Zero deviation and divided census tracts are the identifying hallmarks of a gerrymander.  Achieving zero deviation is virtually impossible without splitting census tracts.  There is no other justification for the practice.

One of the primary goals in the quest for fair redistricting should be the requirement that the smallest unit to be used in redistricting will be the census tract.

Census tracts are basically neighborhoods, or micro communities of interest.  They are designed by the U. S. Bureau of the Census to be demographically homogeneous, relatively permanent, and bounded by natural and/or manmade geographical features. They are statistical subdivisions of counties and do not cross county lines.

“Census tracts generally have between 1,500 and 8,000 people, with an optimum size of 4,000 people. Counties with fewer people have a single census tract.  When first delineated, census tracts are designed to be homogeneous with respect to population characteristics, economic status, and living conditions.  The spatial size of census tracts varies widely depending on the density of settlement. Census tract boundaries are delineated with the intention of being maintained over many decades so that statistical comparisons can be made from decennial census to decennial census.“  U. S. Census Bureau, Cartographic Boundary Files, Geographic Area Description, Census Tracts, 2005.

Various redistricting experts, authorities,  and other interested organizations are also calling for the use of undivided census tracts as the basic unit in redistricting, including:  Model Redistricting Act, Section 4 (a)(6), Redistricting Criteria, issued in 2005 jointly by the Mexican American Legal Defense and Educational Fund, California Common Cause,  the Asian Pacific American Legal Center, and the League of Women Voters of California;  A Proposal for Redistricting Reform:  A Model State Constitutional Amendment, Section 6.E, Americans for Redistricting Reform, January 2009, by Sam Hirsch, formerly of Jenner & Block LLP, Washington, D.C. and currently U.S. Department of Justice; and  Arizona State Constitution, Article 4, Part 2, Section 1 (14.E), as amended by the passage of Proposition 106 by the people of Arizona in the 2000 general election.

For those truly advocating fair redistricting, academia should never accept zero deviation as a norm, nor perpetuate the legal fiction that it is required by the U.S. Supreme Court (or worse, by the Constitution).  Likewise, academia should never accept the division of census tracts as a necessary evil to achieve the goal of substantially equal population.

Since Justice Brennan was the most zealous advocate on the Supreme Court of population equality in districts, Karcher v. Daggett is often cited as a requirement for achieving absolute equality (“zero deviation”) between congressional district populations.  The following quotes of Justice Brennan in this case clearly dispel such a dogmatic misinterpretation of the Court’s opinion.  In fact, the phrase “zero deviation” occurs only twice in Court opinions, one occurrence being in a footnote by Justice Stevens and the other disclaiming its necessity by Justice O’Connor, neither instance being the Opinion of the Court.  It has never been a requirement of the Court.

Opinion of the Court, Justice Brennan:  “Any number of consistently applied legislative policies might justify some variance, including, for instance, making districts compact, respecting municipal boundaries, preserving the cores of prior districts, and avoiding contests between incumbent Representatives. As long as the criteria are nondiscriminatory, these are all legitimate objectives that, on a proper showing, could justify minor population deviations.” [Citations omitted.]  Karcher v. Daggett, 462 U.S. 725, at 740-1 (1983). Justice Brennan also stated in Footnote 6, “A federal principle of population equality does not prevent any State from taking steps to inhibit gerrymandering, so long as a good faith effort is made to achieve population equality as well. See, e.g., Colo. Const. Art. V, § 47 (guidelines as to compactness, contiguity, boundaries of political subdivisions, and communities of interest); Mass.Const., Amended Art. CI, 1 (boundaries); N.Y.Elec.Law 4-100(2) (McKinney 1978) (compactness and boundaries).”  He further stated in Footnote 11, “The very cases on which Kirkpatrick relied made clear that the principle of population equality did not entirely preclude small deviations caused by adherence to consistent state policies.”

 Justice Stevens, concurring:   “The major shortcoming of the numerical standard is its failure to take account of other relevant — indeed, more important — criteria relating to the fairness of group participation in the political process. To that extent, it may indeed be counterproductive.” Karcher v. Daggett, 462 U. S. 725, at 753 (1983).

Justice Powell, with whom Justice Stevens joined, concurring in part and dissenting in part:  “A standard that judges the constitutionality of a districting plan solely by reference to the doctrine of `one person, one vote’ may cause two detrimental results. First, as a perceived way to avoid litigation, legislative bodies may place undue emphasis on mathematical exactitude, subordinating or ignoring entirely other criteria that bear directly on the fairness of redistricting. Second, as this case illustrates, and as Reynolds v. Sims anticipated, exclusive or primary reliance on `one person, one vote’ can betray the constitutional promise of fair and effective representation by enabling a legislature to engage intentionally in clearly discriminatory gerrymandering.”  [Citations omitted.]  Davis v. Bandemer, 478 U.S. 109, at 168 (1986).

Justice Harlan, with whom Justice Stewart joined, dissenting:  “[T]he Court’s exclusive concentration upon arithmetic blinds it to the realities of the political process, as the Rockefeller case makes so clear. The fact of the matter is that the rule of absolute equality is perfectly compatible with `gerrymandering’ of the worst sort. A computer may grind out district lines which can totally frustrate the popular will on an overwhelming number of critical issues. The legislature must do more than satisfy one man, one vote; it must create a structure which will, in fact, as well as theory be responsive to the sentiments of the community.”  Wells v. Rockefeller, 394 U.S. 542, at 551 (1969).

Justice Harlan, in Kirkpatrick v. Preisler, 392 U.S. at 550-552 (1969), ridiculed the concept:  “Marching to the nonexistent ‘command of Art. I, Sec. 2’ of the Constitution, the Court now transforms a political slogan into a constitutional absolute.  Strait indeed is the path of the righteous legislator. Slide rule in hand, he must avoid all thought of county lines, local traditions, politics, history, and economics, so as to achieve the magic formula: one man, one vote. … If the Court believes it has struck a blow today for fully responsive representative democracy, it is sorely mistaken. Even more than in the past, district lines are likely to be drawn to maximize the political advantage of the party temporarily dominant in public affairs. … [T]he question before us is whether the Constitution requires that mathematics be a substitute for common sense in the art of statecraft.”  Justice White, in Kirkpatrick v. Preisler, 394 U.S. at 555 (1969), wrote: “Today’s decisions, on the one hand, require precise adherence to admittedly inexact census figures, and, on the other, downgrade a restraint on a far greater potential threat to equality of representation, the gerrymander. … I see little merit in such a confusion of priorities.”

The prescient warnings of Justices Powell and Harlan and others have been fully realized; extreme adherence to zero deviation has led inexorably to extreme gerrymandering (summum ius summa iniuria).

The Court had strained at a gnat, and swallowed a gerrymander.

The U. S. Supreme Court recently reaffirmed that the Constitution does not require absolute equality in district populations, apparently in a unanimous vote.  “We have since explained that the ‘as nearly as is practicable’ standard does not require that congressional districts be drawn with ‘precise mathematical equality.’”  Tennant v. Jefferson County Commission, 567 U.S. ___ (2012) (per curiam).  The Court made it clear that a plan could not be challenged successfully simply because an alternative plan achieved a lower variance of population.  And despite such allowances by the Court, gerrymanderers will continue to use zero deviation as a cover to gain personal and/or partisan political power.

For unreconstructed proponents of zero deviation or those who may doubt the Court’s intention, the challenge is to cite a case where the Supreme Court has held a redistricting plan illegal or unconstitutional due to relatively minor population variances when a state had consistently followed fair redistricting principles.

The redistricting standards in Iowa apparently allow for a total deviation of two percent. “Congressional districts shall each have a population as nearly equal as practicable to the ideal district population  . . .  No congressional district shall have a population which varies by more than one percent from the applicable ideal district population . . .”  Iowa Code, Chapter 42.4 (1.b).

“[P]opulation equality is such a crude way of equalizing voters that an obsession with very small population deviations seems rather silly.”  Bruce Cain, The Reapportionment Puzzle, (1984), p. 59. As quoted by the Supreme Court of California, Wilson v. Eu, 1 Cal.4th 707, at 754, footnote 12 (1992).

Zero population deviation is a reductio ad absurdum.  There is no perfect census, which is changing even as it is being taken, through births, deaths, and migrations.  Plans are not drawn until a year or more after the census, and elections are held two or more years after.  Districts are based on total population in a futile quest for equally–weighted votes, arguably the worst basis to use for such an impossible goal.  The Court had placed an inordinate reliance on such an illogically simplistic and internally contradictory standard.

With a goal of fair and effective representation, there should be a cohesive approach to respect communities of interest based on a strict use of whole census tracts as neighborhood/micro communities of interest, and, to the extent practicable, use of counties as intermediate/historical communities of interest, and councils of governments as regional/macro communities of interest.  These are perfectly nested communities — census tracts do not cross county lines, and councils of governments are composed of whole counties.

The optimal use of coterminous boundaries and nesting of various types of districts will increase the opportunity for upward mobility of politicians and thus competition (“the rivalship of power”, as Hamilton noted in The Federalist No. 84).  Coherent functionally-compact districts are certainly more capable of mutability or of becoming more competitive than fragmented artificial districts.  Elections will be considerably more responsive to broad political shifts within communities of interest.  Representation will be enhanced by competition over who will best represent the interests of the community.