Mexico goes into Sunday’s election deeply divided: friends and relatives no longer talk politics for fear of worsening unbridgeable divides, while drug cartels have split the country into a patchwork quilt of warring fiefdoms. The atmosphere is literally heating up, amid a wave of unusual heat, drought, pollution and political violence. Opposition presidential candidate Xóchitl Gálvez has focused her ire on López Obrador’s “hugs not bullets” policy of not confronting the drug cartels. She faces former Mexico City Mayor Claudia Sheinbaum, who is running for López Obrador's Morena party. Sheinbaum, who leads in the race, has promised to continue all...