The ACLU filed a constitutional challenge to Ohio's congressional map on Wednesday, seeking action before the 2020 election and using Republican Gov. John Kasich's statements opposing gerrymandering as ammunition.

The American Civil Liberties Union suit filed in U.S. District Court in Cincinnati challenges district maps in effect through 2020 for "an unconstitutional partisan gerrymander" that violates voters' rights to democratically select their representatives. The action is not intended to impact the maps used in this fall's elections, but it could have an impact on maps for 2020.

"The current Ohio map is one of the most egregious gerrymanders in recent history," the suit states. "The map was designed to create an Ohio congressional delegation with a 12 to 4 Republican advantage — and lock it in for a decade. It has performed exactly as its architects planned, including in 2012, when (Democratic) President Barack Obama won the state."

The plaintiffs say their action is unrelated to Ohio voters' approval May 8 of Issue 1, which changes Ohio's system for congressional map-making starting with the next census.

ACLU of Ohio Legal Director Freda Levenson said the 10-year map is being challenged now — so late in the decade — because the legal landscape has changed, with courts laying out clear guidelines for proving partisan manipulation.

If the U.S. Supreme Court directly addresses partisan gerrymandering in either or both of two related cases it's currently deciding, then that rationale could be applied in the Ohio case. If the high court punts, there is still a third case out of North Carolina waiting at the court for action.

Levenson said the timing's also optimal because data is available to show how the maps routinely deliver 75 percent of Ohio's congressional seats to Republicans with only about half Ohio's votes.

"It's the sweet spot in the decade to sue because we don't have to prove that it was going to happen — it's already happened," she said.

Pennsylvania's congressional districts were redrawn earlier this year after the state's Supreme Court ruled the old map was a partisan gerrymander favoring Republicans. The U.S. Supreme Court declined to overturn the use of new districts before this year's midterm elections.

The suit is filed against Kasich, Republican Secretary of State Jon Husted and leaders of Ohio's GOP-controlled state Legislature on behalf of the A. Philip Randolph Institute, the League of Women Voters Ohio and a number of registered Ohio voters who are Democrats.

Kasich, who doesn't hesitate to break from his party, has been outspoken on the need to fix maps created for partisan advantage that are widely seen as contributing to political divisions in Washington.

He filed an amicus brief in the Gill v. Whitford redistricting case that the ACLU cites in its filing. Kasich wrote that "partisan gerrymanders are unconstitutional, are harming our republican government, and readily can be identified and addressed by courts."

Husted, a former House speaker and candidate for lieutenant governor, also has long championed changes to Ohio's system for map-making.

Catherine Turcer, executive director of Common Cause Ohio, which helped lead the Issue 1 effort, said "even one more election using gerrymandered districts is too many."

"This litigation may give Ohioans the fair districts they deserve in 2020 and may strengthen the protections of Issue 1 in the next redistricting cycle," she said.

The ACLU has requested the case be heard by a three-judge panel, as federal law allows in redistricting cases. Levenson said that presumably allows for expedited decisions that will have minimal impact on ongoing election processes.

Any appeal would go straight to the U.S. Supreme Court.