The penalty for leaving Islam is death.
This ‘Law’ has been enforced for 1400 years. Part of the problem here is that the authority to execute people is supposed to be used only by a national government. Two ways that governments kill people: They execute their own citizens, or the government declares war and the professional army kills the enemy. Islam as a religion must not be allowed to retain this ability to terminate people’s lives. Islam implements the killing of others through the authority that Imams exercise. They can field their own militias. This is in conflict with the idea of governmental enforcement of the laws, not to mention government control of the armed forces. Even when governments enact this penalty for leaving Islam within the legal system, this reinforces the idea that once something is Muslim, it cannot revert back to anything else. This can be (And frequently is) applied to ‘waters’ and ‘occupation’ of land as well.
This concept goes well past national boundaries. As a result, this is an international issue that modern nations have and should go to war over. In addition, this law is a major structural problem for Islam.
The penalty for leaving Islam is death is one of the primary factors in the reasons why Sunni and Shiite have not been able to resolve their differences since 690 AD. (Islam was founded in 610 AD) Because the two sides differ in the line of succession of the leadership of Islam, (A major, fundamental difference) each side sees the other as having left Islam. In many of the cases where we hear of ‘sectarian’ violence, this is a major, basic cause. A number of other differences exist in the interpretation of the Koran. (It is human nature for people to differ) When any group interprets the law in any way significantly that is different from others, they see the other side as having left Islam. Either they must change their views, or else be executed. Naturally, the other side sees it the other way round.
Very few disagreements exists with the interpretation of ‘The penalty for leaving Islam is death.’ This cannot do anything but assist violent behavior. Historically, when ‘outsiders’ or infidels are involved, Sunni and Shiite will band together to defeat the common enemy before attempting to deal with the other, which is more of an internal problem.
Execution of people is the sole responsibility of a modern national government, not a ‘religion’. Once again, Islam is in direct conflict with modern governance. Imams wield the power of governments when they can implement this penalty, along with numerous other penalties that Islamic law requires. People and nations will fight violently to resolve these types of issues. It is about the only way to resolve them. Submission is the other. No wonder it results in violence, on both sides.