It might just be game over for the Iowa caucus

The siege of Iowa and New Hampshire has begun.

The two states with privileged places on the presidential primary calendar are finding their roles more threatened than ever before — most recently in the form of a bill introduced in Nevada this week to move that state’s nominating contest to the front of the line in 2024.

On its own, the Nevada encroachment would mean little. For years, Iowa and New Hampshire have successfully defended their one-two position from states eager to jump ahead. But the combination of Iowa’s botched...