Geography
The Role of Redistricting and Gerrymandering in Electoral Geography
Quick fact
In 2012, Democrats won the national popular vote for the House but Republicans gained a 33-seat majority, partly due to gerrymandered district boundaries that concentrated Democratic voters in few districts and spread Republicans across many.
Why this is interesting
During the 2012 U.S. House elections, Democrats won about 1.4 million more votes nationwide, yet Republicans won a 33-seat majority. How can a minority of votes control a majority of seats?
Read the full explanation
Understanding The Role of Redistricting and Gerrymandering in Electoral Geography
Think of electoral geography as the spatial distribution of voters across a country. When redrawing district lines, a party in control can use two main tactics: packing and cracking. Packing concentrates many opposing voters into a few districts, making those districts 'safe' for the opposition but wasting their votes. Cracking spreads them thinly across many districts, diluting their influence. By exploiting where voters live—such as urban areas leaning Democratic and rural areas leaning Republican—a party can draw lines that win more seats than its vote share would otherwise allow. This is why district shapes often look bizarre: they are drawn to gather or scatter specific groups.
A deeper explanation
The mechanism underlying gerrymandering is the geographic clustering of like-minded voters combined with the ability to draw boundaries that exploit that clustering. The key is to maximize the number of seats won with a given vote share by wasting the opponent's votes: each district has one winner, and votes for losing candidates are wasted, as are surplus votes for winning candidates beyond what's needed. By packing opponents into dense districts, their surplus votes are wasted, and by cracking them into districts where they lose by small margins, their votes are wasted as losers. This requires detailed population data and algorithmic drawing of boundaries. The practice undermines the principle of equal representation—the idea that each person's vote should carry equal weight—and can entrench partisan control despite shifts in public opinion. The legal landscape has tried to regulate the practice, but the Supreme Court has deemed partisan gerrymandering to be a political question, leaving the issue largely to states and political processes, which is why it remains a contentious issue in electoral geography.