Gerrymandering

Elections for things like a state legislature or Congress aren't decided by one statewide vote. The state is cut into districts, each electing one representative, and whoever gets the most votes in that district wins the whole seat. That district-by-district structure is what makes gerrymandering possible: a party doesn't need to win the most total votes, it needs to win the most districts. Whoever controls the redistricting process can draw the lines to make that happen.

Two techniques do the work. Packing crams the opposing party's supporters into a small number of districts, where they win by huge margins, but all those extra votes beyond 50 percent plus one are wasted. Cracking does the opposite: it splits the opposing party's remaining supporters across many districts, thinly enough that they fall just short of a majority everywhere else. Combine the two and a party that wins only 40 percent of the vote statewide can still capture most of the seats, because the votes that lose are concentrated and the votes that win are spread efficiently.

Gerrymandered maps don't stay effective forever. Populations shift, neighborhoods grow or shrink, and the carefully built margins erode until the next census forces redistricting anyway. This connects gerrymandering to redistricting itself, the periodic redrawing of boundaries after each census, and to the boundary-drawing theme running through the unit: just as borders get laid over cultures and maritime zones get stacked offshore, districts get laid over voters, and the shape of the line decides who holds power.