Maduro’s Top Rival Has a Problem: Venezuela’s Opposition Won’t Vote

Henri Falcón, who is leading in some polls, must outmaneuver an entrenched ruling administration and plans by opposition parties to boycott the vote

TURMERO, Venezuela—Henri Falcón, the top Venezuelan opposition candidate in Sunday’s presidential election, faces two obstacles to winning: his friends and his foes.

He must not only outmaneuver a ruling administration using state machinery to dominate the vote. Mr. Falcón must also overcome the reluctance of a coalition of like-minded opposition parties that is boycotting a contest they say is rigged.

Mr....