Mr. Mastriano, who promotes Christian power and disdains the separation of church and state, has repeatedly lashed Mr. Shapiro for attending and sending his children to what Mr. Mastriano calls a “privileged, exclusive, elite” school, suggesting to one audience that it evinced Mr. Shapiro’s “disdain for people like us.”

It is a Jewish day school, where students are given both secular and religious instruction. But Mr. Mastriano’s language in portraying it as an elitist reserve seemed to be a dog whistle.