A Michigan court case on gerrymandering made national headlines this week, as a panel of three federal judges ruled that 34 of Michigan’s Congressional and legislative districts are unconstitutional and need to be redrawn prior to the 2020 election.

The three judges -- U.S. Circuit Judges Eric Clay and Denise Hood and U.S. District Judge Gordon Quist -- said Michigan’s last redistricting plan gives Republicans an unfair advantage, and that advantage is so profound that the lines need to be redrawn by Aug. 1.

Evidence shows the maps’ “partisan bias has proven severe and durable; it has strongly advantaged Republicans and disadvantaged Democrats for eight years and across four separate election cycles," the judges said.

It “represents a political gerrymander of historical proportions,” the ruling said.

The lawsuit was filed by the League of Women Voters and several Democrats, including Rashida Tlaib, a former state representative now in Congress representing the 13th District.

If the ruling stands, it could have a big impact on Michigan’s state and federal lawmakers as well as voters.

Here is what Michigan voters need to know.

1. The ruling impacts 15 state House districts, 10 state Senate districts and nine of the state’s 14 congressional districts.

The lawsuit alleged -- and the judges agreed -- that Republican lawmakers who drew the maps in 2011 manipulated the lines to maximize the success of Republican candidates. They allegedly did that by either packing Democratic voters into a few districts, which appeared to be the strategy in metro Detroit, or dividing a Democratic stronghold such as the city of Grand Rapids between multiple districts.

The districts called into question for unconstitutional “packing” or “cracking” voters into certain districts in the lawsuit were: Congressional Districts 1, 4, 5, 7, 8, 9, 10, 11, and 12; Senate Districts 8, 10, 11, 12, 14, 18, 22, 27, 32, and 36; and House Districts 24, 32, 51, 52, 55, 60, 62, 63, 75, 76, 83, 91, 92, 94, and 95.

Click here for maps showing the location of those districts.

2. Thursday’s court decision isn’t the last word.

Michigan Republicans are likely to seek a stay of the ruling, citing the fact the U.S. Supreme Court is deliberating similar cases involving gerrymandering in North Carolina and Maryland, and a decision is expected in June.

In a March hearing in those cases, it appeared the Supreme Court’s conservative majority is reluctant to use federal court intervention in gerrymandering cases, saying states seem to be addressing the issue on their own.

Even if a stay isn’t sought or granted, it seems likely the Supreme Court decision will have a big impact on what happens in Michigan.

3. Thursday’s ruling calls for the Michigan Legislature and Gov. Gretchen Whitmer to redraw the lines by Aug. 1.

If Thursday’s ruling stands, the judges want a new plan by Aug. 1. The plan needs to be developed by Michigan Legislature, which is controlled by Republicans, but the plan must be agreeable to Whitmer, a Democrat.

That timeline could definitely change depending on whether Republicans successfully obtained a stay, and/or what happens in the U.S. Supreme Court.

4. Thursday’s court ruling could have a profound impact on the state Senate.

Although three legislative bodies are affected, the state Senate would be impacted most if the ruling stands. That’s because the ruling calls for the Senate to hold a special election in 2020 using the newly redrawn map.

Since Michigan senators served four-year terms, and they all were elected or re-elected in 2018, a special election in 2020 could cut incumbents’ terms short.

A complicating factor is term limits. Since Michigan senators are limited to two terms, would a special election in 2020 mean second-term senators can’t seek re-election? Or is it possible an exception might be made in this case? Those questions are unresolved.

5. If there is a new map for 2020, it would only be for that election.

Regardless of what happens with the court case, Michigan is scheduled to redraw its congressional and state legislative districts in 2021 based on the decennial Census. That new map will be used starting in 2022.

6. That means Michigan could have three maps in four years, with a different process for each.

The map for the 2018 election relied on the current system, which calls for the Legislature to come up with a plan every 10 years after the decennial Census, and that plan must be approved by the governor. When that last happened in 2011, the Republicans held a majority in the Michigan House and Senate and also controlled the governor’s seat.

Outcry over their plan spurred not only the current lawsuit but Proposal 2, a citizens’ initiative on the November 2018 ballot. More than 60 percent of Michigan voters approved Proposal 2, which shifts the responsibility of drawing Michigan’s state and federal political districts to a 13-member independent redistricting commission consisting of five independent members, four self-declared Democrats and four self-declared Republicans.

The passage of Proposal 2 means whatever happens with the gerrymandering court case, Michigan will has a new process in place for drawing maps in 2021 -- one much different than the process used for the 2018 map and, if it happens, for a new 2020 map.

7. Thursday’s ruling is much harsher on the GOP than the compromise proposed by Secretary of State Jocelyn Benson.

The original defendant in the lawsuit was then-Secretary of State Ruth Johnson, a Republican named in the lawsuit because the secretary of state oversees Michigan elections. Johnson left office at the end of 2018 because of term limits, and her successor was Benson, a Democrat.

In January, Benson proposed a settlement that involved redrawing the boundaries for 11 state House seats - the 24th, the 32nd, the 51st, the 55th, the 60th, the 63rd, the 76th, the 91st, the 92nd, the 94th and the 95th. No state Senate or federal districts would have been impacted under her plan.

Republicans urged the judges to reject Benson’s plan and the judges did, saying Benson “lacks the authority” to enter into such a settlement. The case went to trial in February.

8. There was considerable evidence showing partisan motives in drawing the current map.

In 2011, the national Republican State Leadership Committee “engaged in a national effort to ensure that states redrew their congressional lines during the 2011 redistricting cycle to favor Republican candidates and disadvantage Democrats,” using the name project REDMAP, the judges said in their findings of fact.

The new map meant that Republicans won nine of Michigan’s 14 Congressional seats, even though they never earned more than 50.5 percent of the vote. In the 2014 state Senate election, the GOP won 50.4 percent of the vote but 71 percent of the seats, the judges noted.

Evidence introduced at the trial about the Republicans’ motives included emails, including one by Jack Daly, a former congressional aide, who wrote: “In a glorious way that makes it easier to cram ALL of the Dem garbage in Wayne, Washtenaw, Oakland and Macomb counties into only four districts.”

9. Michigan is part of a nationwide rebellion against gerrymandering.

The Republicans may end up victims of their own success: Their 2011 efforts across the country to create political districts favorable to the GOP resulted in both strong Republican majorities in numerous states as well as considerable backlash.

Thursday’s ruling in the Michigan case is part of a series of victories for legal victories for challengers of gerrymandering.

“We’ve clearly hit a tipping point in partisan gerrymandering litigation around the country,” Thomas Wolf, a lawyer at the Brennan Center and an expert on voting rights, told the Washington Post on Thursday. “As late as 2015, 2016, the idea that voters could walk into court and bring partisan gerrymandering claims and win was far-fetched.”