When Georgia Republicans this year sought to make two legislators’ reelections a tad safer by moving some of their Black constituents into neighboring districts and replacing them with whites, it was the kind of state-level shenanigans that don’t tend to cause a national stir. Then former U.S. attorney general Eric Holder weighed in, urging the governor and the state senate to “reject this attempt to rig the political system.” He didn’t say “see you in court,” but he didn’t have to. Georgia lawmakers backed down, and Holder and his new National Democratic Redistricting Committee sent a message that they are keeping close watch on the shaping of the nation’s political maps. And if flinching turns to fighting, they’ll be looking at the courts as their most important weapon.

Gerrymandering, a term for the creative drawing of electoral boundaries, comes from Massachusetts Gov. Elbridge Gerry, who approved an infamous salamander-shaped district in 1812. To be fair, Americans practiced politically advantageous cartography before Gerry; even Patrick Henry tried to screw over James Madison in the earliest days of the republic by helping put Madison in the same district as James Monroe (Madison ended up winning anyway). State legislators and governors typically hold the power to redraw congressional and state legislative lines after each decennial census, and the politically charged results can resemble reptiles or works of abstract art.

Redistricting is a bloodsport. There ain’t no ‘fair’ in that. Lynn Westmoreland, former Georgia Republican congressman

Ahead of the 2010 census, Republicans mounted an astoundingly successful campaign in dozens of states to snag total power to draw favorable lines. Democrats were caught flat-footed by the Republican State Leadership Council’s “Redmap” plan, in which key races were flooded with $30 million and aided by the 2010 Tea Party wind at the GOP’s back. With total control of capitol buildings in states like Pennsylvania, Ohio and North Carolina, Republicans helped engineer overwhelmingly Republican congressional delegations — even though voters in those states were about evenly split. Using sophisticated software to slice up the electorate down to the block, map-drawers created districts to elect Republicans reasonably safely, while Democrats were packed into blue seats. Democrats did the reverse in states they controlled, such as Maryland and Illinois. Fairness gets lip service at best. “Redistricting is a bloodsport,” says Lynn Westmoreland, a former Georgia Republican congressman who helped lead national redistricting efforts. “There ain’t no ‘fair’ in that.”

The process helped make the U.S. House a safe space for Republicans. Overall, Democratic House candidates bested Republicans by well more than 1 million votes in 2012, yet they were 17 seats short of a majority because of how the lines were drawn. This was not entirely attributable to the smoke-filled back rooms of nefarious data wizards. Democrats cluster in major urban areas, bottling up their political strength. A recent analysis by Cook Political Report concluded that the sharp decline in closely contested U.S. House districts has come far more from voters’ own ideological sorting than redistricting.

With little chance to retake the House given the current lines, Democrats were determined to prepare early for 2020. The NDRC was launched as an umbrella group, with Holder the headliner and former President Barack Obama expected to be involved. “It’s important we have an entity setting priorities for the progressive community,” says Ali Lapp, a board member for the NDRC. “If you care about redistricting, these are the five most important governors races. Here are the [legislative] chambers we can switch.” In 2015, Republicans launched a new Redmap effort for 2020, saying they planned to raise $125 million and swing legislatures in Kentucky, Maine and New Mexico to the GOP. But the group has flown under the radar ever since. Westmoreland worries they’re not getting their act together quickly enough, and wave elections for Democrats could flip the 2010 script.

The fight this time is about more than winning elections. While the NDRC will get involved in key races, it won’t have many opportunities to conquer state capitals. In places like Wisconsin and Ohio, the legislatures are solidly Republican, meaning Democrats’ best shot would be to elect a governor who can veto proposed maps and force bipartisan negotiations. Where Democrats don’t have control, NDRC will spend a lot of its money funding lawsuits and campaigns for bipartisan, independent map-drawing commissions like those in California and Arizona. While removing partisanship is a near-impossible task, Douglas Johnson, a redistricting expert and founder of the National Demographics Corporation, says “they’re pretty clearly better than the legislatures have been at taking the politics out.” Though legislatures are loath to cede power, several states have discussed the idea, with Nebraska and Illinois the most likely to switch to a commission, Johnson says.

Court challenges usually rely on race-related violations of the Voting Rights Act of 1965. The practices of “packing” minority voters into one district or “cracking” them up to dilute their power can violate the law. Lately, Democrats and liberal groups have scored wins against maps they claimed were discriminatory. A federal district court recently ruled that three congressional districts (two held by Republicans) in Texas discriminate against Blacks and Latinos and must be redrawn. Last year Florida and Virginia had their maps thrown out by the courts for racial reasons, helping Democrats pick up four U.S. House seats in the redrawn districts.

Courts have avoided nixing even the most egregious political gerrymandering, though, with the U.S. Supreme Court saying, essentially, “we need a measuring stick that works,” Johnson says. But the legal road could be reaching a sharp turn. In March a federal three-judge panel ruled that Republican-drawn state legislative districts in Wisconsin were so partisan that they violated the civil rights of Democrats. The case now goes to the Supreme Court, which could at last impose limits on partisan line drawing. Either way, cartographers are sharpening their pencils.

OZY reporter Libby Coleman also contributed to this article.