Freedom of Slavery as the south slavery plantations were vital to the souths economy and tarrifs
This answer is on answers.com its really a great website to use just put the question in and yay.
Answer:
scholars have identified three types of cause of decolonization: metrocentric, peripheral, and international. In short, these involve causes in the imperial power, in the colonized territory, and in the wider world.
in my opinion peripheral would not be included on a basic level and you question states only 2 so i would think metrocentric and international.