Ohio’s GOP-drawn U.S. congressional map is an unconstitutional partisan gerrymander, the ACLU alleged in a lawsuit filed Wednesday.

The suit, the latest to target the practice of drawing district lines for partisan gain, points to the map itself, as well as what it calls the “tightly controlled process” Republicans used in 2011 to draw it. The map has routinely elected 12 Republicans to four Democrats, even as the two parties have split Ohio’s statewide congressional vote roughly evenly.

“The 12-4 map was drawn in secret in a hotel room, nicknamed ‘the bunker’ by the map drawers, to which only Republicans had access,” the lawsuit claims. “Versions of the map had to be approved by national Republicans, despite no official role in Ohio’s redistricting statutes for the national Republican Party.”

The complaint describes one district as a “detached shoulder blade with a robotic arm that reaches out from a shoulder of Cleveland into Akron.” Another district it dubs the “Snake on the Lake,” because it “eats its way across the southern border of Lake Erie, ingesting portions of five counties (none in its entirety).”

“The contorted shapes of some of these districts also make clear the length the map drawers had to go to in order to achieve their political goals,” the lawsuit says.

The challengers are asking the court to declare the congressional map an unconstitutional gerrymander and to block its implementation in future elections.

The ACLU is bringing the complaint on behalf of 16 voters as well as the Ohio A. Philip Randolph Institute. It names Gov. John Kasich, Secretary of State John Husted, Ohio House Speaker Pro Tempore Kirk Schuring and Ohio State Senate President Larry Obhof as defendants.

Earlier this month, Ohio voters passed a ballot initiative that creates a bipartisan process for drawing congressional district lines. But the lawsuit notes that, under the measure, if that process fails, Ohio’s legislature will be able to fall back on producing maps with a simple majority.

The complaint also quotes a friend-of-the-court brief Kasich signed in a Supreme Court redistricting case from Wisconsin, that said “partisan gerrymanders are unconstitutional, are harming our republican government, and readily can be identified and addressed by courts.”

Husted, one of the defendants, responded to the suit in a statement:

If the way the congressional lines were drawn was such an issue for the ACLU, A. Philip Randolph Institute and League of Women Voters, why did they wait six years to file a lawsuit challenging the maps? These groups should respect the will of Ohio’s voters who overwhelmingly approved a constitutional amendment earlier this month that established a new, bipartisan process for drawing congressional districts starting in 2021.

The Supreme Court is expected to issue rulings in the Wisconsin case and in a separate partisan gerrymandering case out of Maryland before its current term ends. One or both of those rulings could clarify when, if ever, partisan gerrymanders are unconstitutional.

In addition to Ohio and Wisconsin, Republicans in Pennsylvania, Michigan, North Carolina, Virginia, and Florida, among other states, used the redistricting process at the start of the decade to draw lines that benefited their party. Those maps have given the GOP a major advantage in the state legislative and congressional elections that have followed.

Ohio has faced a number of lawsuits for its election practices in recent years. A challenge to its system of purging the voter rolls was heard by the Supreme Court this year, with a ruling also expected this term. The Supreme Court in 2016 allowed the state’s cutbacks to early voting to go into effect for the presidential election, after an appeals court reversed a lower court’s decision to block the cuts.

This story has been updated with a response from Secretary of State Husted

Read the lawsuit below: