1) The Revolutionary Guards (IRGC) push their way to the foreground of political power in Iran.
The IRGC controls security in the Iranian Regime, which means violently quashing political protests and training terrorists, but they could take political power if the situation in Iran escalates, which would turn Iran into a purely military regime.
2) Economic sanctions on Iran will cause the Regime to collapse, leading to civil war and the disintegration of Iran into several ethnic and sectarian statelets.
This collapse may be delayed a little, while European states try to save the deal, but make no mistake, Europe will pull out, leaving Iran with just Russia and China. Then, Russia will withdraw, given that it is trying to distance itself from the mullah’s regime in Syria in order to curry favour with Israel. China will follow soon after, given its needs for Saudi oil investments
The mullahs are also failing to deal seriously with the US withdrawal and are at risk of suffocating their economy all on their own, which will mean that collapse is just around the corner.
Mohammed Al-Shaikh, a Saudi writer with al-Jazirah newspaper, wrote: “The only thing the [Iranian Regime] can do is to tolerate this situation and try to buy time in hopes that President Trump’s term ends and another president, who is not as strong and decisive as Trump, is elected. However all available indicators show that Trump will serve another presidential term, i.e. sanctions will stay in effect and the mullahs will not be able to tolerate this anymore…
I think the fall of the mullahs’ sectarian and expansive policies will change the region’s situation drastically, and it seems the Americans are also convinced of this.”
However, there is a third option that Al-Shaikh has not presented and that is the fall of the Regime and the ascendency of the Iranian Resistance.
Both of the above options are terrible for the Iranian people, but there is a fully-functional government in exile that is already operating in France: The National Council of Resistance of Iran (NCRI). The NCRI has already elected a government for the transitional period after the mullahs fall and until they can transfer power to the Iranian people.
This is the option that the US should support, power to the Iranian people.