How battle over redistricting could decide control of Congress

With the rancorous 2020 U.S. election now over, Democrats and Republicans are girding for another national political battle with enormous stakes: redistricting.

The once-a-decade process of redrawing electoral maps can determine which party controls Congress. Though Democrats hold power in Washington, Republicans have the redistricting advantage heading into 2021. Redistricting occurs every 10 years after the U.S. Census completes its decennial count of the national population.

Because the number of US House of Representatives seats allocated to each state is driven largely by population, some states whose population declined will likely lose seats to others that have seen growth. This year, Texas and Florida are among the states expected to gain seats, while New York, Ohio and Pennsylvania are among those that will likely lose seats. Each state uses the census data to draw congressional districts, as well as new state legislative districts.

In most states, the legislature produces the maps, with the governor often having veto power. Lawmakers often try to draw lines in a manner most favorable to their party, a process known as gerrymandering. Gerrymandering occurs when district lines are deliberately manipulated to benefit one party over another. Federal law prohibits racial gerrymandering, in which minority communities are intentionally disadvantaged, but partisan gerrymandering, in which lines are altered based on how residents voted, is permitted.

The U.S. Supreme Court ruled in 2019 that federal judges have no jurisdiction over partisan gerrymandering, though the decision does not prevent state courts from weighing in. Both the Pennsylvania and North Carolina state Supreme Courts have found extreme partisan gerrymandering violates their state constitutions. In general, the most aggressive current gerrymanders are seen in Republican-controlled states, thanks to the party's massive victories in statelevel elections in 2010. That has allowed Republicans in Wisconsin, for example, to maintain an iron grip on the legislature, even as Democrats have won statewide races.

After Democrats failed to make major gains in November at the statehouse level, Republicans will have sole power to draw the lines for 181 seats in the 435-seat U.S. House, compared with only 49 for Democrats, according to an analysis by the Brennan Center at New York University. Some experts say Republicans could use redistricting alone to flip the half-dozen House seats needed to regain control of the chamber from Democrats in the 2022 congressional elections. The biggest immediate concern is a months-long delay in the release of census data due to the coronavirus pandemic. Last week, officials said states would not receive detailed figures until September.

As a result, the two states that hold legislative elections in 2021, Virginia and New Jersey, will use their old maps. Meanwhile, around half of U.S. states have legal deadlines calling for new maps to be completed in 2021, which could be impossible given the delay; experts say many states will likely ask courts for extensions.

Some good government groups are worried the delay could lead to more extreme gerrymandering, since it would leave little time for any legal challenges to make their way through the courts before the 2022 elections in November. The Supreme Court's decision in 2013 to eliminate a key section of the Voting Rights Act will also make it more difficult for civil rights groups to prevent gerrymandering. In years past, states with a history of racial discrimination in elections were required to get "preclearance" from the federal government before making any changes to voting laws, but the court struck down that provision.