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Whenever I speak about our polarized politics, the first or second question I get is almost invariably about redistricting. Most Americans who know that our political system is not working the way it is supposed to don't know what specifically is wrong. But gerrymandering is something that clearly stands out for many. That is true even for Bill Clinton, who spoke about polarization and dysfunction at the 2013 Clinton Global Initiative and singled out gerrymandering as a prime cause.

The reality, as research has shown, is that the problem is more complicated than that. The "big sort," in journalist Bill Bishop's term, where Americans increasingly concentrate in areas where they are surrounded by like-minded people, is a major factor in the skewing, and the homogeneity, of districts. Other partisan residential patterns, including the fact that Democrats tend to live in more high-density urban areas, while Republicans tend to cluster in suburban and rural enclaves, matter. And the Senate, which represents states, not districts, is almost as polarized as the House. (Indeed, according to the National Journal voting records for the last Congress, it is more polarized—there was no overlap between the parties, meaning that the most conservative Democratic senator was to the left of the most liberal Republican senator.) Senate primaries, just like House ones, skew heavily toward each party's base, and senators respond. And the permanent campaign pushes lawmakers to stick with their team, even if some of the team's votes go against an individual member's more moderate or bipartisan grain.

But acknowledging all of that is not to say that gerrymandered districts don't have a significant impact on the sorry state of American politics. Gerrymandering has leached much of the broader heterogeneity out of congressional districts, contributing to the echo-chamber effect, where members' ideological predilections are reinforced, and not challenged, back home. A corollary is the racial segregation of districts—the fact that so many Republican districts now have barely more than trace elements of minorities, giving GOP lawmakers little incentive to reach out or be sensitive to issues that resonate with those groups. Partisan gerrymandering skews results away from the broader sentiments of voters in a state, as much research, including a new study by Duke University's Jonathan Mattingly and Christy Vaughn, demonstrates powerfully.

And, of course, gerrymandering has helped create a huge number of districts that are fundamentally safe for one party. This is sometimes done by a dominant party in a state "packing" the other party's districts to limit its chances in other districts. Other times it is done by an unholy alliance of both parties to keep all incumbents safe. Gerrymandering adds both to the homogeneity of districts and to making low-turnout primaries dominated by ideological activists the only meaningful elections.

More broadly, gerrymandering moves House and state-legislative elections away from any meaningful responsiveness to the will of the people. And the pattern of lawmakers choosing their voters instead of voters choosing their lawmakers creates more disaffection and cynicism among the public.

Almost every other democracy of significance avoids such problems by creating nonpartisan bodies to draw district boundaries.

How do we reform the redistricting process in this country? Through independent commissions that can use multiple criteria—not just equal population in districts, but factors such as competitiveness, compactness, and communities of interest—to create districts that more closely reflect broader public views. But creating independent commissions is no easy task; doing so through legislative action requires buy-in from the same lawmakers who draw the district lines—and who have the least incentive to give up their power via reform.

With the exception of Iowa, where the state legislature turned the drawing of lines over to a nonpartisan agency in 1981 after disputes and deadlocks handed the power to the Iowa Supreme Court, the one outlet for change has been using the initiative process to implement such commissions. That process worked in Arizona in 2000 and in California in 2008, and while the results are no panacea, the reforms have brought more competitiveness and more fairness to the process.

Guess what? The ability of voters to take control of the redistricting process away from partisan legislators and create a nonpartisan and independent process may disappear next year. The Supreme Court has taken up a case, Arizona State Legislature v. Arizona Independent Redistricting Commission, challenging the constitutionality of the commission. If the Court strikes down the Arizona commission, it will also mean the end of the California commission, and of any future efforts to bypass self-interested legislatures to reform the redistricting process.

The main issue here is the meaning of the elections clause of the U.S. Constitution, which states, "The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof." In previous litigation involving Electoral College reform, as legal scholar Rick Hasen has analyzed in an article for the Hastings Constitutional Law Quarterly, courts have defined "legislature" to include lawmaking actions taken by state voters via initiative—in a fashion that Hasen saw as settled law. But it is no longer settled. The fact that the Supreme Court decided to take this case—instead of leaving in place a federal district court decision that the Arizona state constitution allows voters, by initiative, to exercise legislative powers—opens up the issue again.

The Arizona case is not just a dry question of the meaning of a clause in the Constitution. It was brought under partisan auspices. The commission's post-2010 redistricting effort ticked off Republicans, who say it was biased in favor of Democrats. The commission has five members; two each are chosen by Republican and Democratic lawmakers, with the fifth member chosen by the other four. On the most recent map, one Republican member abstained, and one voted no. The lawsuit was not the first attempt by Republicans to tilt the commission in its favor. In 2011, the Legislature voted to remove the commission's chair and tried to remove the two Democrats; the effort to oust the chair was rebuffed by the Arizona Supreme Court. This lawsuit followed.

There is a second issue in the lawsuit: whether the Arizona Legislature has standing to bring such a suit. Of course, the case could be rendered moot if the Supreme Court denies standing. But the greater likelihood is that the Court will grant standing and move on to the broader issue.

If the Supreme Court throws out these redistricting commissions, we can kiss good-bye any efforts to effectively change the redistricting process, to reduce the pernicious effects of gerrymandering. It would take away one of the few weapons available to those who want to find ways to create more-representative and less-polarized representation in our democracy, and to reduce the cynicism about a system now tilted against the American electorate, broadly defined. We are struggling to find avenues to ameliorate the worst effects of our tribalized politics. What a shame if the Supreme Court shuts off one of the major avenues.

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