Why did Saudi Arabia execute Shiite cleric Sheikh Nimr al-Nimr now?

The Saudis had Nimr in custody since 2012, sentencing him to death in 2014. The cleric had been a vocal critic of Saudi Arabia¡¯s ruling royal family for years, going as far as threatening Shiite secession in the minority¡¯s eastern homeland in 2009.

The Jan. 2 execution of al-Nimr, alongside 46 others, mostly al-Qaida members, sparked a crisis with Iran. Protesters in Tehran set the Saudi Embassy on fire, and the Iranian government threatened ¡°divine revenge¡± against the kingdom. Riyadh severed diplomatic and commercial ties with Tehran, and Saudi allies Bahrain, Sudan and the United Arab Emirates filed diplomatic protests.