Question:
If a Shia imam leads the prayer, can Sunni Muslims follow him?
Answer:
To understand this, scholars often explain that Shia groups are not all the same. Broadly speaking, they fall into two main categories.
First, there are those who may be called the political or moderate Shia. Their main belief is that after the Prophetﷺ ﷺ, leadership should have gone to Ali. They criticize the early political decisions that resulted in Abu Bakr and Umar becoming leaders. They may even rely on weak reports claiming that the Prophetﷺ designated Ali as successor. However, they do not claim that Ali has divine qualities. They do not worship him. Their position is a historical or political opinion, even if it is mistaken. In fact, within the science of hadith there were narrators who had mild Shia inclinations, yet their narrations were accepted by scholars and appear even in collections like Sahih Bukhari and Sahih Muslim. Their views were considered errors, not disbelief.
Then there are the extreme groups, sometimes called the ghulaat. Here the beliefs become far more serious. Some claim that Ali possesses divine qualities or knowledge of the unseen. Some even claim he was not truly buried but was taken to heaven and remains alive, observing everything. Others extend similar supernatural attributes to Hasan, Husayn, and later imams. In extreme cases they declare many companions such as Abu Bakr, Umar, Aisha, and Muawiyah to be disbelievers. Some even perform acts resembling worship directed toward Ali. Certain symbolic practices also exist where five revered figures—the Prophetﷺ ﷺ, Ali, Fatimah, Hasan, and Husayn—are represented as sacred figures. When beliefs reach the level of attributing divine powers to humans, scholars consider this a form of shirk and reject such doctrines.
So what is the ruling regarding prayer behind such individuals? If the imam merely holds the belief that Ali deserved leadership but does not attribute divine qualities to him and does not engage in shirk-like practices, then many scholars say praying behind him may still be valid. But if the imam belongs to an extreme group that deifies Ali, curses the companions, or practices forms of worship directed to individuals, then Muslims should not pray behind him. Therefore the ruling depends on examining the actual beliefs of that particular imam and group.