Why are Saudi Arabia and Iran rivals?
The rivalry revolves around ethnicity, religion, oil and influence. Saudi Arabia is predominantly Arab and Sunni while Iran is majority Shia and Persian. The former has the largest proven oil reserves in the world. The latter has the second largest. Both countries consider themselves to be the leader of the Muslim world. Their animosity flared in the wake of the 1979 Iranian revolution. Iran's newly installed ruling Shia clergy unnerved conservative Sunni Saudi Arabia. Iran's Ayatollah Ruhollah Khomaini exacerbated matters by criticizing Saudi Arabia for its support of Saddam Hussein during the Iran-Iraq war in the 1980s. While relations between the two countries improved slightly after Ayatollah Khomaini's death in 1989, they soured again when Iranian President Mahmoud Ahmadinejad came to power in 2005.
What is the evidence of this rivalry?
Before allegations of an assassination plot surfaced, the most prominent evidence of Saudi Arabia and Iran's rivalry was their efforts to influence the many protests across the Middle East, which has sparked a proxy war for regional dominance. Saudi's King Abdullah felt so threatened by the democratic revolutions that he announced a series of measures such as raising of public-sector salaries and launching new social programs to shore up stability. While Iran has historically fed off unrest – recent conflicts in Iraq, southern Lebanon and Gaza have increased its power – the protests in Syria, its ally, hit close to home for Mr. Ahmadinejad. The rivalry between Saudi Arabia and Iran was perhaps most keenly felt in Bahrain. When pro-democracy demonstrations erupted, Saudi Arabia sent in troops to crush them, fearing Shia protesters would overthrow Bahrain's Sunni king.
What are the implications of this plot on this rivalry?
The immediate result with be further entrenchment on both sides of the Saudi-Iran divide. Relations have recently been somewhat strained between the United States and Saudi Arabia over the events of the Arab Spring. The historic alliance between the two countries will undoubtedly strengthen in the face of the alleged Iranian plot. Iran will become further isolated. The stage is set for a potentially dangerous confrontation.