Our Expert Voices conversation on what comes next in Iran vs. Saudi Arabia.

Saudi Arabia has succession well in hand. Iran, on the other hand, has designated no successor to the Supreme Leader and is riven by deep political divisions united only in the belief that the perpetuity of their rule is contingent on exporting the Islamic Revolution.

Lacking his predecessor Ayatollah Khomeini's charisma and stature, Iran's Ayatollah Khamenei consolidated his rule by placing loyal supporters of the Islamic Revolution in all branches of government and granting the Revolutionary Guard unprecedented economic and political power. These transformations yielded a sectarian-driven expansionist and interventionist foreign policy, the continuity of which vouchsafes the legitimacy of any Supreme Leader.

The bottom line: Saudi Arabia has already had its succession and is forging ahead with needed reforms. With no clear successor, Iran's factions will vie with one another to escalate sectarian policies abroad in order to build revolutionary credentials for the next Supreme Leader at home.

Other voices in the conversation:

• Bernard Haykel, Middle East scholar, Princeton University: Don't expect de-escalation
• Dalia Dassa Kaye, political scientist, RAND: Youth will drive change
• Suzanne Maloney, Iran policy advisor, Brookings: Sectarian tensions are baked into the relationship
• Karim Sadjadpour, Middle East policy analyst, CEIP: The rivalry will grow