In single-member districting, a district's voting yields only a single representative to Congress. In multi-member districting, however, a district's voting yields multiple representatives to Congress.

As I will explain in this column, for a number of reasons, single-member districting is far less democratic than multi-member districting. It further entrenches already-entrenched incumbents, and effectively disenfranchises minorities voting within a given district.

But unless the Supreme Court steps in, the single-member districting process will doubtless continue. After all, why would the very incumbents whom single-member districting favors, vote to abolish the practice?

In 1962, in Baker v. Carr, the Supreme Court courageously announced the principle of one-person one-vote -- which defeated certain kinds of political manipulation by ensuring that Congressional districts had to be equal in population. Baker was radical and controversial at the time it was decided. But now, everyone agrees that the Court was right to intervene.

It's high time for the Court to hand down a new Baker: One that takes aim at the pernicious practice of single-member districting. Single-member districting not only infringes on the basic right to vote, it also infringes on the right of free political association.

How Political Gerrymandering Undermines Voting and Association Rights

As a recent column by Edward Lazarus discussed in detail, politicians are becoming ever more adept at manipulating district boundaries to favor the outcome they desire. Yet permitting the representatives to choose the represented, and not the other way around, inverts the very concept of democracy.

Political gerrymandering has given incumbents an advantage -- often, an unbeatable one. As a result, elections have become less meaningful.

Few seats in the House of Representatives and in state legislatures are now truly up for a fair contest by a serious challenger. Many representatives are so certain to be re-elected -- particularly thanks to political gerrymandering -- that they might as well be the monarchs of their districts.

Because they need not worry about re-election, these representatives need not worry about being accountable to voters' beliefs and preferences. And voters who form a minority within the district are especially susceptible to being ignored: Why should a politician listen to those who both vote against him, and have no chance of unseating him?

Instead of acquiring political power by convincing voters of the wisdom of their legislative agenda -- and making compromises to appeal to minority constituents -- political parties are simply attempting to solidify their power by engaging in imaginative and ingenious line drawing. Because the nation is so sharply divided, and because so few seats are contestable, the benefits of creative line-drawing--four or five districts here and there--generate tremendous payoffs.

Consequently, the national political parties have taken greater interest in the redistricting process. Districting has become a tool that the parties use to increase their strengths and carry out their policies in the United States House of Representatives.

Less time is spent on listening to, and wooing, constituents; more is spent on redistricting to make sure voting outcomes are preordained. Voting rights are harmed -- and, for some voters, decimated.

Suppose, for example, that the state wants to draw a district that will elect a Democrat. It will create a district where the majority of voters are Democrats. The state will not create a district that is 100% Democratic because that will waste Democratic votes. So, the state would put Republicans in that district instead precisely so that their votes are wasted.

In theory, a State that was 60/40 Democratic could disenfranchise all the Republicans by creating numerous 60/40 Democratic districts. If this were done, it would be, in effect, as if the States' Republicans had lost the right to vote.

How Political Gerrymandering Violates the Right to Political Association

This kind of aggressive redistricting violates not only the constitutional right to vote, but also the constitutional right of political association. Under the First Amendment, individuals have the right to associate with like-minded others, in the service of political causes. But redistricting that is designed to split up otherwise-powerful groups, and reduce them to powerlessness, defeats that right of association.

What if the Republicans who are a minority in one district want to team up with other Republicans in another district so that they can elect a Republican representative? The answer political gerrymandering gives is: Too bad. Since the state had already decided to place the Republicans in separate districts, they are forced to be separate.

Of course, any scheme districting will always naturally separate certain people who would like to associate; Republicans who live at opposite ends of a state are out of luck if they'd prefer to share a district. But my point is that political gerrymandering intentionally tries to destroy the right of association, by breaking up naturally associated persons to make it harder for them to organize, and elect representatives with views akin to their own.

For its own purpose, the government forces certain associations, and discourages others. Republicans -- or, in other Districts, Democrats -- who know they will be perpetual losers, may not even bother to associate politically at all. And their discouragement will be a predictable result of intentional state action motivated to separate them politically from like-minded individuals.

Voters of color, in particular, have suffered from political gerrymandering. The Court has increasingly frowned on the primary device for giving effect to their electoral preferences: the creation of majority-minority districts -- seeing this device, wrongly, as a form of racial discrimination.

In part because of the Court's disapproval, states have drawn many fewer majority-minority districts in the post-2000 redistricting round than in the previous decade. As a consequence, voters of color have suffered a loss in representational opportunity.

How Multi-Member Districting Can Undercut Political Gerrymandering

That's all bad news, of course -- and the worst of it is, none of this is bound to improve anytime soon, unless the Supreme Court intervenes. Plainly, it is not going to change its mind to bless majority-minority districts. But there is something the Court can do to improve the situation.

Single-member districts are especially susceptible to political gerrymandering -- and thus especially damaging to the basic constitutional rights to vote, and to political association. Conversely, multi-member districts with cumulative voting can vindicate these rights to a much greater extent.

Imagine, again, our 60-40 Democratic state. And imagine, once again, that it's cut up into numerous 60-40 Democratic districts. But now imagine that each district elects three members. And also imagine that voting is cumulative each voter would get three votes and they can plump all their votes for one candidate. As long as Republicans vote along party lines, prefer the same Republican candidate, and all vote for that candidate, cumulative voting would guarantee them as least one seat.

Suddenly, no one can ignore the Republicans anymore. They are likely to elect at least one representative in each district, if they unite. And if they build alliances with Democrats, they may have even greater control. Whereas in the past, it seemed the Republicans were entirely powerless, now their power has been significantly revived.

Supreme Court Intervention Is the Only Solution

Our society is too heterogeneous and we have too many cross-cutting political identities to tolerate political gerrymandering in its present form. Yet politicians will never, on their own, be able to resist the temptation to manipulate the lines for their own benefits -- any more than they could restrain themselves from creating districts that violated the one person-one vote principle before Baker v. Carr.

The Supreme Court not only should, but must intervene. Striking down single-member districts will not eliminate political manipulation entirely. But it will go a long way toward reducing the damage done by this incumbent-protection device. Thus, the Supreme Court should rule that single-member districts are unconstitutional.