The story: Moderate ex-president Hassan Rouhani (2013-21) has criticized some conservatives who attacked his policies in a recent presidential debate. Rouhani’s chief diplomat Mohammad Javad Zarif has also raised eyebrows with a fiery defense of his foreign policy on state television. While the interventions have garnered support from those in favor of reform, conservatives have lashed out.

Zarif’s bold return to publicly back the sole Reformist candidate signals a clear understanding that the June 28 elections may be...