WASHINGTON (CN) – Urging the Supreme Court to crack down on Wisconsin Republicans for political gerrymandering, an attorney for voters warned the justices Tuesday that turning a blind eye will only embolden Machiavellian lawmakers to embrace advancing technology.

“If you let this go, if you say we’re not going to have a judicial remedy for this problem, in 2020 you’re going to have a festival of copycat gerrymandering the likes of which this country has never seen,” Paul Smith, an attorney at the Campaign Legal Center, said at Tuesday’s arguments.

Smith warned that new techniques and social science metrics mean the next round of redistricting will not be “your father’s gerrymandering.”

Republican majorities have controlled both houses of the state Legislature since 2011. Armed with the results of the 2010 census that year, lawmakers hired a consultant and a political science expert to help divide up the state’s legislative map, working from the offices of a law firm they called the “map room.”

Though the state lawmakers say their changes were above board, 12 Democratic voters led by professor William Whitford claimed in a federal complaint that the map was divided with the express purpose of favoring the party of Lincoln.

They claim the lawmakers did this by employing cracking and packing, the two major methods of gerrymandering.

In cracking, legislatures draw districts so voters from one party are scattered across districts, limiting their impact on each race. As its name suggests, packing does just the opposite, jamming a large number of co-partisans together to create one, landslide district.

Relying on a host of new social-science metrics that the Wisconsin voters presented as evidence, a divided panel of three federal judges found the state map unconstitutional last year, triggering a mandatory appeal to the Supreme Court.

The social-science metrics relied upon by Whitford and the other voters were at the heart of Tuesday’s arguments, with Chief Justice John Roberts referring to them a “gobbledygook” and questioning their durability given that others presented to courts in similar cases have been proven wrong in the past.

“That’s going to come out one case after another as these cases are brought in every state,” Roberts said. “And that is going to cause very serious harm to the status and integrity of the decisions of this court in the eyes of the country.”

Wisconsin Solicitor General Misha Tseytlin echoed this point, saying the metrics are far from a scientific certainty. He warned against adopting a scheme that requires courts to handle redistricting by sorting through mountains of evidence presented by experts and social scientists.

“You could have federal courts engaging in battles of hypothetical experts deciding, well, what would it be under this map or that map?” Tseytlin said. “So I think that’s a nonstarter for that reason.”

The case is one of the first partisan gerrymandering challenges to come before the Supreme Court in a decade, putting the court, and specifically Justice Anthony Kennedy, in the position to hand down a landmark decision.

As he traditionally takes the role of swing vote on the court, Kennedy often takes the spotlight in close cases. Compounding this attention for the case at hand, however, is a concurring opinion he wrote in the 2004 decision Vieth v. Jubelirer.

Though the court sidelined the political gerrymandering question in Vieth, Kennedy wrote separately that he would be open to hearing a future challenge if someone could develop a workable test.

Whitford and his co-plaintiffs offered what they hope will be the magical test that could swing Kennedy. Endorsed by the U.S. District Court, the test would require courts to determine whether a map is designed with “discriminatory intent” and creates a “large and durable” discriminatory effect that has no other reasonable explanation.

Called the efficiency gap, the metric employed by the District Court in Wisconsin measures the number of wasted votes in each district, defined either as votes for a losing candidate or those cast for a winner in excess of the bare minimum needed to win the seat.

Where the metric shows a larger efficiency gap for one party than another, Wisconsin voters say it could mean the state’s map is unconstitutionally based on partisanship.

Roberts questioned whether average voters could understand opaque numbers, inundating the Supreme Court with appeals every time a court rules on a partisan gerrymandering case only to have its impartiality called into question.

Justice Stephen Breyer disagreed, saying it would be easy for people to understand the metrics at issue if they were explained as ensuring a given party wins the majority of seats in a legislature regardless of whether they win the majority of the votes in an election. But Roberts dismissed this explanation, saying it essentially endorses proportional representation.

Smith meanwhile said the measures are important because they can help give the courts guidance for when a partisan map has gone too far and rises to the level of unconstitutionality. The metrics on which his clients relied throughout the case, Smith said, are the same ones legislatures have used to carve up the maps in the first place.

Kennedy had few questions about the test Wednesday, focusing instead on whether the Whitford group has standing to bring the case at all.

He wondered whether the plaintiffs’ standing issue would be erased if the court considered the case “a First Amendment issue, not an equal protection issue.”

“Would that change the calculus so that, if you’re in one part of the state, you have a First Amendment interest in having your party strong or the other party weak?” Kennedy asked.

Tseytlin, the Wisconsin solicitor general, said that the change would make no difference. He argued that voters should not have the ability to challenge an entire state’s map when they only live in some of the districts at issue.

It would be unreasonable to let voters in a different state challenge Wisconsin’s congressional map, he said, and allowing voters in a single state legislative district to do the same for a statewide map would be just a problematic. Tseytlin also said granting Whitford’s group standing would make it easier for voters to challenge partisan gerrymandering than racial gerrymandering, an outcome Roberts agreed would be “arresting.”

But Smith said this outcome would not be surprising because partisan and racial gerrymandering cases are fundamentally different. While black voters in one district might not share the same interests as blacks in another district, Democrats generally have more common purpose.

“You wouldn’t want to assume that some African American from a different part of the state has a collective interest with people over here in this party of the state just because of race,” Smith said. “That’s just stereotyping.

Kennedy focused on the hypothetical question of whether a voter in Madison would be able to challenge a law in another town that bars candidates of a certain party from placing road signs during a campaign. Tseytlin said a candidate in the town would certainly be able to bring a challenge, but that a voter in Madison certainly would not be.

Erin Murphy, a partner at the Washington firm Bancroft, appeared to rankle Kennedy by deflecting his question about laying out map rules via constitutional amendment, requiring a certain amount of partisanship to be present alongside the traditional principles of gerrymandering.

Speaking to reporters outside the Supreme Court on Tuesday, Smith, the attorney who argued for the voters, would not hazard a guess at Kennedy’s leaning.

“One thing I don’t do is come out in front of a bunch of cameras and predict justices’ votes,” Smith said. “I do think he understood our position and he seems quite concerned about where the country is right now.”

This story is developing…