若政权垮台或接近垮台，风险不在于平稳过渡，而在于迅速失序。Burcu Ozcelik与Bernard Haykel都警告，Iran可能滑向内战：Islamic Revolutionary Guard Corps可能分裂，地方武装可能扩张，外部势力也可能武装Baloch、Kurds、Azeris与Arabs等族群。由于Iran约只有50%人口为Persian，中央国家若被削弱，对Iran本身与整个区域都可能造成灾难性后果。
战事持续时间则取决于三项力量。依Dina Esfandiary所述，对美国而言，经济代价愈高，尤其能源价格愈高，Donald Trump承受的停战压力就愈大；对Iran而言，关键在于武器库存被消耗或摧毁的速度，以及Ayatollah Ali Khamenei死后哪个派系取得优势。至于民主转型，历史数据极不乐观：Antonio Barroso指出，自1945年以来60次外部支持的领导层更替尝试中，只有7次形成至少维持10年的民主；若案件被指涉及美国，26次中仅2次成功；在中东则是0次。
Bernard Haykel outlines three possible endings to the war in Iran: regime collapse, regime survival with a softer stance and a deal with the US, or regime survival with an even harder revisionist posture; he judges the third outcome most likely. Bloomberg Economics likewise sees regime change as unlikely in the short term, and prediction markets assign it only a 36% probability. At the same time, Donald Trump says the only deal he will accept is unconditional surrender.
If the regime falls or nears collapse, the main danger is not orderly transition but rapid disorder. Burcu Ozcelik and Bernard Haykel both warn that Iran could slide into civil war: the Islamic Revolutionary Guard Corps could fracture, local armed groups could expand, and outside powers could arm communities such as the Baloch, Kurds, Azeris, and Arabs. Because only about 50% of Iran is ethnically Persian, a weakened central state could produce catastrophic consequences for both Iran and the wider region.
The duration of the fighting depends on three main forces. As Dina Esfandiary argues, for the US, higher economic costs, especially higher energy prices, would increase pressure on Donald Trump to end the war; for Iran, the key variables are how quickly weapons stockpiles are depleted or destroyed and which faction becomes strongest after the death of Ayatollah Ali Khamenei. A democratic transition appears especially unlikely: Antonio Barroso notes that of 60 foreign-backed leadership change attempts since 1945, only 7 produced democracies lasting at least 10 years; in alleged US-linked cases, only 2 of 26 did, and in the Middle East, 0 did.