On Tuesday, the Supreme Court will consider whether state legislatures violate the Constitution by deliberately drawing legislative districts for partisan advantage.

The ghosts of Justices Felix Frankfurter and William Brennan will be hovering behind the bench.

Those two judicial antagonists fought their last duel on March 26, 1962. Frankfurter was incensed that day, because his colleagues had voted, 6-2, to ignore a warning he had written 16 years earlier.

The new case was Baker v. Carr, a challenge by Tennessee voters to the grossly inequitable districts from which their legislators were elected. Tennessee lawmakers had not redrawn districts in more than half a century. In that time, the state’s population had nearly doubled, with most of the growth taking place in urban areas. In On Democracy’s Doorstep: The Inside Story of How the Supreme Court Brought "One Person, One Vote" to the United States, J. Douglas Smith recounts how the political efforts of urban voters to to change the system failed; rural legislators refused to undermine their own power. The voters finally turned to the federal courts, alleging that, by undervaluing urban votes, the system violated their Fourteenth Amendment right to “the equal protection of the laws.”

Standing in their way was Frankfurter’s 1946 opinion Colegrove v. Green, which rejected the identical claim from a group of Illinois voters. The vote in Colegrove was 4-3 (the court was short two justices); Frankfurter’s opinion, for only three of the four-justice majority, argued that inequality of representation was an issue “of a peculiarly political nature and therefore not meet for judicial determination.” He added, “Courts ought not to enter this political thicket.”

After hearing argument twice in Baker v. Carr, however, the justices voted 7-2 for a different result. No more would malapportionment be a “political question”: courts could hear and decide challenges like that of the Tennessee voters.

That decision didn’t resolve the Tennessee challenge; it simply told the lower court that it could hear evidence and make a decision. Even so, no one at the time regarded this as an easy question. In fact, Justice Charles Evans Whittaker, agonized by the deliberations in Baker, suffered a nervous breakdown, recused himself from the case, and eventually resigned his seat.

Justice Brennan, however, wrote for the majority with his customary confidence. “Judicial standards under the Equal Protection Clause are well developed and familiar,” he wrote, “and it has been open to courts since the enactment of the Fourteenth Amendment to determine, if on the particular facts they must, that a discrimination reflects no policy, but simply arbitrary and capricious action.”

As scholar Mel Urofsky reports in his book Dissent and the Supreme Court, Frankfurter began his oral dissent with a bitter prophecy: “Today the Court begins a process of litigation that it requires no prophet to say—and Cassandra was sometimes right—will outlast the life of the youngest member of this Court.”

A month later, Frankfurter suffered a stroke; in August 1962, he resigned. Meanwhile, Urofsky reports, “His prophecies of a judicial nightmare never materialized. Although the entrenched state legislators fought to prevent reapportionment, once it happened and a majority population controlled a majority of legislative seats, opposition died out.”

On Tuesday, the court will face another similar choice: should it proclaim an equal protection rule against partisan gerrymandering, or walk away from the issue as a “political thicket?” As in Baker v. Carr, the question is whether there is a rule that will end the practice without embroiling the courts in constant litigation they will have no reliable way to decide.

Like the challengers in Baker v. Carr, the challengers in Gill—voters in Wisconsin—are confronted with an apparently adverse precedent a decade and a half old: Vieth v. Jubelirer, a 2004 challenge to U.S. House districts in Pennsylvania carefully drawn to shift congressional seats from Democratic to Republican control. The challenge failed: four of the nine justices voted for a per se rule that partisan-districting challenges were always “political questions.” Justice Antonin Scalia wrote for these four that “no judicially discernible and manageable standards for adjudicating political gerrymandering claims have emerged.” Justices John Paul Stevens, David Souter, Ruth Bader Ginsburg, and Stephen Breyer, in three separate dissents, disagreed, proposing three different possible standards.

Determining the result, as so often, was Justice Anthony Kennedy. Kennedy agreed that the plaintiffs in Vieth had not proposed a workable test. However, he said, “I would not foreclose all possibility of judicial relief if some limited and precise rationale were found to correct an established violation of the Constitution in some redistricting cases.”

This is very similar to the result in Colegrove v. Green, in which Frankfurter wrote for three justices. Three justices joined a dissent written by Justice Hugo Black, who would have moved forward with the plaintiffs’ challenge. The deciding vote came from Justice Wiley Rutledge, who said that apportionment cases were “justiciable,” but that the short time remaining before the election meant that in that particular case “the cure sought may be worse than the disease.”

That brings us to Tuesday’s argument. The plaintiffs in Gill have presented the strongest possible evidence of a deliberate plan by the Republican Party, after its victory in the 2010 elections, to skew the state’s districts to lock in their power for the foreseeable future. (Robert Barnes of The Washington Post provides a readable summary of the evidence.) A three-judge federal court (of the kind that hears districting cases) concluded, 2-1, that the legislature had drawn the plan with the intention of locking Democrats out of power.  The majority announced this test:

The First Amendment and the Equal Protection clause prohibit a redistricting scheme which (1) is intended to place a severe impediment on the effectiveness of the votes of individual citizens on the basis of their political affiliation, (2) has that effect, and (3) cannot be justified on other, legitimate legislative grounds.

The court based this conclusion, in part, on studies that showed a new measure called the “efficiency gap” (EG)—which shows how many votes each party’s voters “waste” because they are cast in districts where the other party has won. (Eric McGhee, one of two statisticians who developed the “gap” measure, explained that “wasted” votes...

...include any votes cast for a losing candidate, as well as those cast for a winner in excess of the number required to win. ... Parties that gerrymander try to saddle the opposing party with more wasted votes by ‘packing’ that party’s supporters into a small number of districts it will win handily and ‘cracking’ the rest into districts that the party narrowly loses. The EG is just a summation of all the packing and cracking in a plan.

The majority in the lower court relied on the EG, and other measures, to conclude that its “unjustifiable, intentional impediment” test was met, and that Wisconsin’s districts were unconstitutional.

At the Supreme Court level, Wisconsin’s government argues that the new test is merely a plea for “proportional representation,” where seats would be awarded not in winner-take-all elections but by the overall proportion of the vote. In addition, the state government argues that the legislature’s districts can’t be gerrymanders because they are “traditional districts”—in essence, they don’t look any different from districts that might have produced more Democratic winners.  Gerrymanders are odd and funny-looking, the argument implies. In addition, the state argues that the plaintiffs lack “standing to sue” because they are challenging the statewide map rather than only their own districts.

As a matter of short-term partisan interest, the Republican party stands to benefit tremendously from a victory for Wisconsin. Long-term interest, however, may be different. The Wisconsin Republican Party is Hannibal Lecter today, but could be a chalk outline in ten years. (By some measures, Maryland, the solid-blue state where I work, is one of the most gerrymandered states in the Union—enthusiastically and skillfully districted to produce Democratic majorities in legislature and the federal House delegation.) No one disputes that partisan districting has grown more ruthless and effective over the past quarter-century, as statistical expertise, demographic sophistication, and computer algorithms have grown more powerful. A Supreme Court decision for Wisconsin will encourage even more extreme district-rigging on both sides.

On Tuesday, some of the justices will hear the ghost of Felix Frankfurter whispering like Cassandra in their ears. The robust voice of William Brennan, however, will counsel courage.

For all his brilliance, Frankfurter’s deference and dithering made little long-term impression on the law. Brennan, meanwhile, is despised by conservatives for his liberalism—but few of them question his influence. “He is probably the most influential justice of the century,” Justice Antonin Scalia said in 1996. Brennan’s judicial tests tend to survive because they are workable and lawyer-like. Baker v. Carr did not plunge the court into an impassable thicket, and it shaped the U.S. into a modern democracy. That democracy is now threatened by the creativity of partisan hackery.

Gill will show us whether the Roberts Court has the intelligence to find a remedy, and the courage to apply it.