This week, the Supreme Court heard oral arguments in the Gill v. Whitford case, posing the prospect of a national ruling that could limit partisan gerrymandering for the first time.

Though this particular case is about the Wisconsin state assembly, the potential national implications are broad. It's likely that Democrats will have a very difficult time retaking the US House of Representatives in the coming years in part because of gerrymandering. (One recent analysis found that Democrats could get 54 percent of the vote nationwide and end up with only 47 percent of the seats.)

Now, the impact of partisan gerrymandering can sometimes be exaggerated. It isn't the only reason that election results only occasionally match vote totals, and gerrymandering doesn't benefit Republicans exclusively.

Still, gerrymandering particularly infuriates many voters because it feels so unfair. Letting partisan politicians — or their appointees — draw congressional districts reverses the normal order of politics. Voters are supposed to choose their politicians. Gerrymandering lets politicians choose their voters.

Indeed, several decades ago, Canada dealt with public outrage over this very topic — and adopted major reforms that helped solve the problem.

What Canada did

"Canadian reapportionment was highly partisan from the beginning until the 1960s," writes Charles Paul Hoffman in the Manitoba Law Journal. This "led to frequent denunciations by the media and opposition parties. Every 10 years, editorial writers would condemn the crass gerrymanders that had resulted."

Independent commissions now handle the redistricting in every Canadian province

Eventually, in 1955, one province — Manitoba — decided to experiment, and handed over the redistricting process to an independent commission. Its members were the province's chief justice, its chief electoral officer, and the University of Manitoba president. The new policy became popular, and within a decade, it was backed by both major national parties, and signed into law.

Independent commissions now handle the redistricting in every province. "Today, most Canadian ridings [districts] are simple and uncontroversial, chunky and geometric, and usually conform to the vague borders of some existing geographic / civic region knowable to the average citizen who lives there," writes JJ McCullough.

"Of the many matters Canadians have cause to grieve their government for, corrupt redistricting is not one of them." Hoffman concurs, writing, "The commissions have been largely successful since their implementation."

But American experiments with redistricting commissions have had mixed results

So why hasn't the US done this yet? One reason is that in Canada, there was a long tradition of the national parliament being involved in the redistricting process. But the US leaves the boundary-drawing to the states. The national government and the courts have only interfered for two main reasons: to keep each district roughly equal in population, and to combat racial discrimination.

So a national law requiring independent redistricting commissions in each state would go against the US tradition of state independence, and might not even be constitutional. Barring a dramatic Supreme Court anti-gerrymandering ruling — a possibility Vox's Dylan Matthews explores here — independent commission reforms would likely have to happen on the state level.

There are no truly nonpartisan redistricting commissions in the US

And it's important to note that, depending on the details, these commissions can be little better than the system that preceded them. Some US states have ostensible redistricting commissions, but let politicians name the appointees. "Those commissions are not really independent per se, they're just a separate venue where Democrats and Republicans can hash out their differences," Eric McGhee said, a fellow at the Public Policy Institute of California, told me in 2014.

The specifics of the commission's instructions also matter. "Some of these commissions are specifically charged with creating competitive districts, but that process has costs to it," Nicholas Goedert, a postdoctoral fellow at Washington University in St. Louis, told me in 2014. "You can end up with districts that are not as amenable to representing minority interests."

Only six US states use commissions to do their redistricting, but none of them have fully embraced the Canadian solution. The key difference is that Canada's commission members are all nonpartisan — they're mostly judges, political scientists, or retired civil servants. But our states with redistricting commissions, like California and New Jersey, reserve many seats for members of political parties.

"There are no truly nonpartisan redistricting commissions in the United States," political scientist Bruce Cain of Stanford University told me in 2014. Iowa uses a nonpartisan agency that's not permitted to take party registration into account, but it still gives final say to the governor and legislature.

How California's commission works

California's commission does take several steps toward independence. It doesn't let politicians specifically choose commissioners — instead, it uses a complex selection process with thousands of applicants that includes random drawings as well as input from the legislature. And while the commission reserves five seats for Democrats and five for Republicans, it has four "tie-breaking" seats for people of neither major party.

But in 2012, California Democrats won 62 percent of the House vote, and got 72 percent of the seats — so some have argued that the state just ended up gerrymandered anyway. Yet McGhee, the researcher from the Public Policy Institute of California, told me those kinds of numbers are to be expected. That's because the US only elects one winner from each district — so the losing voters in each district don't affect the House delegation at all. When one simulates various districts and election outcomes under such a system, the winning side naturally ends up with some advantage in the results — a winner's bonus.

Though McGhee was originally skeptical of California's commission, he had come around when I talked to him in the spring of 2014. "I think they did a great job. Compared to the previous decade, the new plans were more fair, more compact, and provided better minority representation," he said. As for reported attempts by Democrats to influence the process, McGhee said, "If you talk to the commissioners, they say, 'Yeah, we knew that was going on, we could tell which people were likely shills for one side or the other.' The only question is whether the outside forces will play the commission better next time around."

Replacing gerrymandering with independent commissions won't solve all our problems. But 50 years of Canadian experience shows that it can make elections more fair — and that it's one reform that the new Holder-Obama group should seriously consider pushing for in the states.

This article was originally published in 2014. It has been updated to reflect recent events.

Watch: How gerrymandering works, and how to fix it