Demands that governments adopt Islamic law are not new, and in fact the legal codes of many Islamic states combine Shariah with laws drawn from European models. In recent years, calls for Shariah often come from groups that are locked out of political participation by authoritarian and undemocratic regimes. Shariah finds grassroots support when governments are corrupt and incompetent. In northern Nigeria, for example, the recent adoption of Shariah followed a period of highly corrupt and entirely undemocratic military rule, followed by a transition to a democratic government that is also plagued with corruption. In Pakistan, likewise, periods of corrupt democratic rule have alternated with periods of corrupt military rule.
Islamic law is very complex.
Centuries of legal scholarship created a vast store of decisions, some of which are widely accepted, while others are accepted only in a few regions. In the Islamic Republic of Iran, for example, Shariah is the basis for law, but legislators do not always agree about the implication of Shariah for a modern government. Iranians elect representatives to Parliament, and these representatives should be able to pass laws. However, Iran also has an unelected Supreme Judicial Council that examines all proposed laws in light of their understanding of Shariah. While both bodies claim to base laws on Shariah, in fact only the unelected body has authority to declare what is Shariah, and what will become law.