In the repressive Islamic Republic of Iran, a cleric isn’t a very popular thing to be nowadays. Mohsen Kadivar is a celebrated exception. A theorist behind Iran’s struggling democracy movement, the modest mullah packs lecture halls like a pop star and attracts readers like a pulp-fiction author. Students in his graduate philosophy classes at Tarbiat Modarres University in Tehran hang on his every utterance. Kadivar, 44, has found academic stardom a dangerous occupation in Iran—in 1999 he was jailed for 18 months for his ideas. But his scholarly perseverance has led to breakthroughs in one of the great intellectual quests of our anxious age: reconciling Islamic traditions and modern democracy. “Kadivar puts his finger on the burning issues for progressive Muslims,” says Iranian reformist Mostafa Tajzadeh. “He has broken taboos which others were too afraid to even approach.”

A student revolutionary during the Shah’s reign, Kadivar enrolled in the Shi’ite seminary in the holy city of Qum after Ayatullah Ruhollah Khomeini came to power, spending 17 years there as a student and teacher. To the dismay of hard-line clerics, his most important work presents a devastating critique of velayat-e faqih, the Shi’ite Muslim doctrine expounded by Khomeini that effectively grants the power of dictatorship to a top Shi’ite cleric. Kadivar argues that because the concept was conceived by clerics rather than by Allah, it cannot be considered sacred or infallible. And if clerics have no God-given right to rule, he says, that means that Muslims may freely select their government in a democratic Islamic republic. Kadivar has also formulated a theory on why terrorism is forbidden in Islam—an indirect reproach to an Iranian regime that is widely accused of backing terrorist groups.

Kadivar has written that there are six contradictions between traditional Islamic teachings and modern norms of human rights—for example, the status of women in society. He believes the religion was meant not to be static but to be adapted to the times. “We cannot use a historical interpretation of religion in the modern world,” he says. Although Kadivar does not consider himself a political activist, he admits that he is driven by a desire to undo religious despots who have hijacked the Islamic revolution. “What the people wanted was something different,” he says. “Who were [the mullahs] to destroy it?” Iran’s clerical court recently threatened to defrock Kadivar if he persists in voicing such views. Although he is free to don civilian attire now that he has left the Qum seminary, he says he will keep wearing his clerical robes as a symbol of defiance. If his message spreads, he could be instrumental in showing people beyond Iran how they can be good Muslims and good democrats too.