American elections aren’t what they used to be: Thanks to relentless, politically driven gerrymandering, fewer and fewer congressional seats are truly competitive. Millions of Americans are locked into districts where their vote will never elect the party of their choice. But gerrymandering is also notoriously hard to fix. Many sitting lawmakers owe their seats to districts that have been wildly contorted to create secure seats. So asking legislators to ban gerrymandering often means asking them to endanger their own jobs. Nevertheless, the stars may soon align for opponents of part...