North Carolina may be a swing state in presidential politics, with polls showing Hillary Clinton now leading Donald Trump.
But there's no question who will win most of the state's 13 House congressional districts in November.
"It's virtually certain that Republicans will hold their 10-to-3 advantage, regardless of what happens in the presidential race," said David Wasserman, an analyst with Cook Political Report. "The districts are simply far too polarized."
That electoral lock may prompt the Supreme Court to take a new look at the old question of whether extreme partisan gerrymandering is unconstitutional, denying voters an equal chance to have their voices heard.
Lawyers from North Carolina and Wisconsin are challenging GOP-drawn electoral maps that ensure Republicans win a majority of seats in Congress or the state house, even when a majority of voters statewide lean in favor of Democrats.
And they are reasonably confident the justices will take up one or both of the cases in the term ahead.
"We think there are five justices interested in devising a legal standard to stop partisan gerrymandering," said Gerry Hebert, executive director of the Campaign Legal Center, a public interest group that advocates for voting rights and fair elections. He said rigged races are "a significant reason for the hyper-partisanship and political gridlock we currently see in state and federal politics."
Repeatedly in past decades, the justices have said they were troubled by partisan gerrymandering, but stopped short of finding a plan unconstitutional.
Justice Anthony Kennedy cast the fifth vote in 2004 to reject a gerrymandering claim from Pennsylvania, but said a state would cross the line if one party freely admitted it drew the districts to deny the other party's "right to fair and effective representation." He also warned of the "threat" posed by computer programs that make it easier for lawmakers to draw district lines to rig outcomes. If the courts don't intervene, he wrote then, "the temptation to use partisan favoritism in districting in an unconstitutional manner will grow."
In the North Carolina case, lawyers say they have the evidence Kennedy is looking for.
When GOP lawmakers redrew the congressional map in 2011, they moved more black voters into two districts that had elected black Democrats and gave Republicans a safe majority in 10 of the 13 districts. In February, however, a three-judge panel called the plan a "racial gerrymander" and ordered changes.
Republican leaders met in Raleigh to quickly redraw the lines, this time saying they would not use race, but instead, party affiliation. The result was the same 10-3 advantage, and they acknowledged their aim was to lock that in.
"We want to make clear," said state Rep. David Lewis, that "we are going to use political data … to gain a partisan advantage on the map" and maintain "our partisan advantage." There is "nothing wrong with political gerrymandering. … It is not illegal," added state Sen. Bob Rucho.
In early August, lawyers for the North Carolina Democrats seized on those comments in an appeal to the Supreme Court and urged the justices to decide on partisan gerrymandering this fall, when they review the racial gerrymandering case from North Carolina in McCrory vs. Harris.
Two days later, Common Cause filed a separate suit before a new three-judge panel in North Carolina asking it to strike down the state's congressional plan. "If there was ever a time for the courts to take a look at this, this is it," said Bob Phillips, executive director of Common Cause North Carolina. "This is a competitive state, where [President] Obama won narrowly in 2008, and [Mitt] Romney won narrowly in 2012. But the congressional delegation does not reflect that."
Lewis and Rucho, the authors of the redistricting plan, slammed the lawsuit as "just the latest in a long line of attempts by far-left groups to use the federal court system to take away the rights of North Carolina voters."
In 2012, 51% of North Carolina voters cast House ballots for a Democrat, yet Republicans won nine of the 13 seats to Congress. One Democratic incumbent narrowly won in a Republican-leaning district, but stepped aside in 2014, when it became clear that he would not win.
While North Carolina may be extreme, it is in line with the national trend. Competitive House races are rare, since districts are drawn to favor Republicans or Democrats. In 2014, the average margin of victory for a House candidate was 35.8%, according to Ballotpedia, a nonpartisan almanac of election data.
Pennsylvania, which has voted Democratic in national elections but has a Republican-controlled Legislature, regularly sends 13 Republicans and five Democrats to the House. Ohio, another toss-up state, sends 12 Republicans to the House, along with four Democrats.
Virginia, which twice voted for Obama and has two Democratic senators and a Democratic governor, has been sending eight Republicans and three Democrats to Congress. On the other side of the Potomac River, Maryland leans Democratic, and its Democratic-controlled Legislature drew districts that gave its candidates seven of eight seats in the House.
The Wisconsin case focuses on the state house and the electoral map drawn when Republicans took full control in 2011.
A year later, 51% of the voters cast ballots for Democrats, yet Republicans still won a supermajority of 60 of 99 seats in the Assembly.
"Wisconsin has the most extreme partisan map in the United States," Hebert said.
In May, a three-judge panel heard arguments on whether the plan is unconstitutional, and a ruling is expected shortly. If the judges uphold the plan, the challengers say they will file an appeal directly with the Supreme Court.
Unlike other federal cases, election and voting cases are heard by three-judge panels, and their rulings go directly to the Supreme Court, where the justices are required to either affirm or reverse the decision.
The problem of gerrymandering has a very long history. In 1812, a Boston newspaper drew a cartoon that depicted a salamander-shaped district that favored the candidate of Gov. Elbridge Gerry, and thereafter such odd-looking districts were dubbed "gerry-manders."
But these days, an electoral district map can be drawn with neat lines that nonetheless effectively assure one party will win a supermajority of seats in Congress or the state house for the next decade.
Ideally, map makers give their party's candidates districts with 55% to 60% of their favored voters, while giving the other party's candidates fewer districts that include 70% to 80% of their likely voters.
University of Chicago Law Professor Nicholas Stephanopoulos and Eric McGhee of the Public Policy Institute of California devised a formula for measuring an electoral map's efficiency in winning seats for its party. The Wisconsin house plan stood out, because Republicans did not lose a single seat from their 60-seat majority in 2012, even though most voters cast ballots for Democrats.
"That's exactly what was planned," Stephanopoulos said. "This is all about partisan advantage. You don't need squiggly lines or weird shapes. You tell the computer: Give me the greatest number of seats. You give all of your candidates a small but reliable margin of victory so the seats won't flip."
Stephanopoulos and McGhee used the "efficiency" formula to track state-by-state legislative races back to 1972. In the 1970s and '80s, gerrymanders tended to favor Democrats slightly, with California and Illinois among the worst offenders, they said. After the census of 1990 and 2000, the election maps tended to favor Republicans slightly.
This decade is different, Stephanopoulos said. "Now the advantages are much larger, and they are very pro-Republican," he said. "We now see very extreme gerrymanders that skew the makeup of Congress and the state legislatures."
The lawmakers in charge, like those in North Carolina and Wisconsin, believe the high court has given them a green light to draw maps for political advantage, he said.
Stephanopoulos hopes the justices will intervene. "I think it would be a very positive development for democracy if the court puts a limit on gerrymanders," he said.