Scott Applewhite / AP

If the Supreme Court were a stock market, the last few years have been as a bull market in conservative constitutional theories. With a tenuous but real 5-4 conservative majority in place, advocacy groups raced to get their pet theories before the Court. In some cases—campaign finance and gun rights, for example—the race paid off, producing 5-4 wins for radical shifts of doctrine. In others (think about public-employee unions) it has not.

Bull markets tempt investors into unwise wagers. History, I suspect, will so regard the appellants in Evenwel v. Abbot, the “one-person-one-vote” (OPOV) case decided Monday. In Evenwel, the Court unanimously rejected an advocacy group’s invitation to throw American politics into turmoil, and in the process to shift power from immigrants to natives, from non-whites to whites, from young people to the aging, and, by coincidence, from the Democratic to the Republican Party.

The needed votes, it now appears, were never there. The Court’s decision was unanimous; equally important, the majority opinion by Justice Ruth Bader Ginsburg attracted six of the Court’s eight justices, including Chief Justice John Roberts and Justice Anthony Kennedy. Even more importantly, the six-justice majority not only decided against the conservative theory, it made it much harder for advocates to pursue the conservative theory in future cases.

Evenwel was a challenge to Texas’s scheme of districts for its state senate. That map conformed to the basic one person, one vote rule—that is, the districts were divided up so as to produce rough equality (within a deviation of 10 percent or less) of the total population within each district.

Beginning in 1962, a series of landmark cases held that states couldn’t consciously favor some kinds of voters over others. (For a good account of the old regime, see On Democracy’s Doorstep by the historian J. Douglas Smith.) The skew was toward rural districts, regarded as more virtuous than what used to be called “the mob,” meaning people in urban areas.

The language of these cases was sometimes inexact, but the basic rule was clear: within a rough 10 percent margin, districts were to be drawn on the basis of raw population—counting, that is, not only voters but those who, by age, criminal conviction, or citizenship status, could not cast ballots. In only one case did the Court permit any deviation from that principle; that case, Burns v. Richardson, approved a Hawaii map that counted only permanent residents of the state. Hawaii argued that its circumstances were unique: Because it had so many military personnel and tourists, it said, its map would be distorted by counting them. The Court approved that Hawaii map— “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.”

The principle rested there until 2013. Then the Project on Fair Representation rushed into federal court to challenge the new Texas senate map. (PFR’s other major recent cases have been Shelby County v. Holder, which gutted the Voting Rights Act’s “preclearance” requirement, and Fisher v. Texas, which seeks to do the same to affirmative action in higher-education admissions.)

PFR cited language from the one person, one vote cases that used the term “voters”; the Equal Protection Clause, they argued, required “citizen voting-age population” (CVAP) rather than total population as the basis for drawing districts. CVAP districting would upend the maps of all 50 states—reducing the clout of cities and boosting suburbs and exurbs, which tend to be whiter, older, and more conservative.

In other words, it would restore much of the effect, if not the justification, of the old, pre-one person, one vote system.

Because it was a challenge to a districting map, federal statutes required it to be heard by a three-judge district court. Late last year, that court rejected the claim, holding that states could use either total population or CVAP—it was “a choice that the Supreme Court has unambiguously left to the states.”

Losers in three-judge cases are entitled to an appeal. Unlike a petition for review, the Supreme Court must decide an appeal, either by hearing argument or by summarily affirming the decision below. By choosing to appeal, PFR unknowingly set the stage for a major defeat.

Recall that the lower court said that states could choose either total population or CVAP. The plaintiffs asked the high court to hold that states must choose CVAP. The state of Texas asked the justices instead to affirm the District Court’s rule that states could use either.

The seven-justice majority disappointed both sides. Reviewing the language and history of the Constitution generally, and the Equal Protection Clause in particular, Ginsburg concluded, “the rule appellants urge has no mooring in the Equal Protection Clause.” Texas’s current map was fine; but the Court wouldn’t agree that the state could have used CVAP if it chose. Ginsburg wrote that “we need not and do not resolve whether, as Texas now argues, States may draw districts to equalize voter-eligible population rather than total population.”

If the Court had held that either basis was okay, it seemed predictable that some conservative legislatures would move to use CVAP. After Monday, that would be unwise. Go ahead and try to use CVAP, the opinion suggests. Somebody will sue you and then, a few million dollars later, you’ll find out whether it’s okay. Oh, and if you read this opinion, you know it probably isn’t.

Ominous words for those who favor the conservative basis, especially as they were backed by a thorough “originalism”-style discussion of the history of representation under the Constitution—a history that clearly favors total population as the basis for drawing districts.

The opinion drew no dissents. Justice Clarence Thomas concurred because, he argued, there is no federal rule about apportionment—states should be free to go back to the old pre-Warren Court representational hijinks. Justice Samuel Alito also concurred, but his separate opinion seeks to undermine the majority’s arguments in favor of population. Ginsburg’s citations to the thought of the Framers, and the debates over the Fourteenth Amendment, are irrelevant, Alito suggested, because “the fight over apportionment was about naked power, not some lofty ideal about the nature of representation.”

This is about as cogent as writing, “the majority describes Ben & Jerry’s product as ‘ice cream,’ when in reality it is nothing more than a sugary frozen concoction blending iced dairy products with various fruits and candies.”

Apportionment is always about power—but seldom more nakedly than in Evenwel.

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