But for all the zeal on the ground, none of it may matter as much as a case heading to the Supreme Court, one that could transform political maps from City Hall to Congress — often to Democrats’ benefit.
A bipartisan group of voting rights advocates says the lower house of the Wisconsin Legislature, the State Assembly, was gerrymandered by its Republican majority before the 2012 election — so artfully, in fact, that Democrats won a third fewer Assembly seats than Republicans despite prevailing in the popular vote. In November, in a 2-to-1 ruling, a panel of federal judges agreed.
Now the Wisconsin case is headed to a Supreme Court that has repeatedly said that extreme partisan gerrymanders are unconstitutional, but has never found a way to decide which ones cross the line.
Some legal scholars believe this could be the year that changes that. If that happens, they say, an emphatic ruling against partisan gerrymanders would rank with another redistricting decision: Baker v. Carr, the historic 1962 case that led to the principle of one person, one vote.
“My feeling is that there is increasing concern within the court about the extent of partisan gerrymandering over the last 10 or 15 years,” said Richard H. Pildes, a constitutional law professor at the New York University School of Law. “I do think this is a pivotal moment — a big, big moment.”
Gerrymandering has always been contentious. But the extraordinary success of a Republican strategy to control redistricting by capturing majorities in state legislatures in the 2010 elections has lent urgency to the debate.
Today, at a time of hyperpartisan politics and computer technology that can measure political leanings almost house by house, Republicans control legislatures in 33 states, 25 with Republican governors. They have unfettered command over the boundaries of at least 204 congressional districts — amounting to nearly half the 435-seat House.
In contrast, Democrats’ share of state legislature seats has shrunk to a level not seen since Warren G. Harding was president, according to the National Conference of State Legislatures. And in recent years, their numbers in the House of Representatives have hovered near levels last seen during the Truman administration.
Partly because of the Voting Rights Act, gerrymanders based on race are flatly illegal, but ones based on partisan intent remain in limbo.
The Wisconsin case heads four legal actions on partisan gerrymanders that the Supreme Court could consider and, perhaps, consolidate. In Maryland, another three-judge panel will hear arguments over whether a Democratic legislature gerrymandered House districts in 2011 to oust a 10-term Republican congressman.
In North Carolina, a June hearing is scheduled in a suit over the unabashedly partisan carving of the state into 10 Republican and three Democratic House seats — this in a state with more registered Democrats than Republicans.
The state representative who drew that map said he had engineered 10 safely Republican seats only “because I do not believe it’s possible to draw a map with 11 Republicans and two Democrats.”