After three years on the throne, King Salman bin Abdul-Aziz Al Saud and his son Crown Prince Mohammed bin Salman are pursuing the most aggressively sectarian and anti-Iran policy in modern Saudi history. The Wahhabi clerical establishment is an enthusiastic partner, which is good internal politics for the royals.
The Saudi antipathy for Shiite Iran predates the Islamic Revolution. The Saudis distrusted the shah and his imperial ambitions, and the anti-monarchist ideology of the Islamic Republic has only worsened their relationship with Persia. But Kings Abdullah and Fahd sought a measure of detente with Iran even during the height of the Iran-Iraq War, fearing that animosity could spiral out of control. Abdullah even sent a Saudi Shiite diplomat to be ambassador to Tehran, the one and only time a Shiite has served as a Saudi ambassador. Salman severed relations completely after the execution of a Saudi Shiite cleric prompted demonstrations against the Saudi Embassy in Tehran.
