The next round of redistricting shouldn’t sneak up on anyone. After coverage of the recent Supreme Court decisions and renewed interest in state-level races because of their role in selecting who draws district lines, parties and political observers are tuned in to the mapmaking process. But there’s one aspect that hasn’t been discussed enough.

In short, too much success can be a bad thing when it comes to drawing the next set of political maps.

One of the biggest complaints about gerrymandering is the lack of competitive districts, which could lead people to the conclusion that the goal of political parties drawing the lines is to create as many safe districts as possible. But that’s not the case.

While partisan redistricting contributes to the lack of Toss-up seats, each party’s goal is not to draw a batch of completely safe districts, but to draw safe-enough districts.

For example, party cartographers don’t want to draw districts with a partisan performance of 65, 70 or 75 percent, but something closer to 55 percent. The goal is to spread favorable voters over as many districts as possible to give your party nominee a considerable edge under most circumstances.

In an article by Reid Wilson in The Hill, a veteran Democratic data analyst described it best. “The GOP gerrymandering efforts rely on the most efficient distribution of GOP voters across as many districts as possible, the idea being to waste very few votes in each victory margin,” Tom Bonier said, referring to Republican efforts prior to the 2012 elections. “Combined with the population trends in many exurban areas, as they become more racially and ethnically diverse, the gerrymanders can become somewhat less effective the closer we get to the next decennial redistricting.”

Immediate vs. longterm gains

After they’ve earned the right to draw the maps by winning state elections, parties must balance the desire to maximize gains immediately with the reality that a map needs to withstand changes in the political environment over the course of a decade.

For example, in Pennsylvania, Republicans drew the map prior to the 2002 elections that elected 12 Republicans and seven Democrats. But the map took a hit mid-decade when Pennsylvania voters voiced their disapproval with President George W. Bush in the 2006 and 2008 elections by electing 12 Democrats and seven Republicans to the House. Republicans recovered in the 2010 elections to close out the decade with a delegation of 12 Republicans and seven Democrats again.

More recently in Michigan, Republicans drew the map prior to the 2012 elections that elected nine Republicans and five Democrats. But the map couldn’t withstand a backlash to President Donald Trump last cycle, and voters elected seven Republicans and seven Democrats. Now there are just six Republicans after Rep. Justin Amash left the party to become an independent.

In Illinois, Democrats drew the map prior to the 2012 elections that has held up well, excepting some mid-decade hiccups. It immediately turned the delegation from 11 Republicans and eight Democrats after the 2010 elections to 12 Democrats and six Republicans, and now has just five Republicans and 13 Democrats.

In Texas, the GOP-drawn map is showing signs of strain as Republicans lost two seats in the 2018 elections and Democrats have a half-dozen more takeover targets next year.

Apex of electoral performance

Democrats’ potential challenge in the next round of redistricting will be drawing new lines at the apex of electoral performance.

If they are successful in 2020, the freshest data will cover two of the Democrats’ best election cycles in recent history, due in large part to a backlash against Trump. But Democrats must assume that their political standing will be diminished at some point in the next 10 years, including when Trump won’t be in office or as big of a part of the political conversation.

If there’s a Democratic president in 2021 and the party controls at least one chamber in Congress, Democrats will likely lurch to the left with their policies. That could help Republicans bounce back in the 2022 midterm elections as voters seek to pump the brakes on Democratic control, and immediately put pressure on new congressional maps drawn by Democrats to perform as desired.

The Supreme Court’s decision in June — that federal courts can’t rein in partisan gerrymanders — gave a green light to state lawmakers to carve their states up to their party’s greatest advantage. 

Of course, Democrats won’t turn down the opportunity to take that redistricting test. That would mean they will do some of the hard work in 2020 by winning state elections. (For a detailed update on the redistricting battle, check out Kyle Kondik’s recent analysis for Larry Sabato’s Crystal Ball.) But drawing the lines won’t be easy because of the challenge in projecting demographic changes, voter sentiment toward the two parties and the national political environment in a post-Trump era.