Nigeria played an active role in the spread of militarism to other African countries, and this happened through law. After independence, former British colonies in eastern and southern Africa struggled to staff their judiciaries with African judges. Beginning in the mid-1960s, states including Uganda, Tanzania, and Botswana solved this problem by retaining judges from the Caribbean and West Africa, especially Nigeria. To understand how colonial law and postcolonial solidarities shaped Africa’s military dictatorships, this chapter focuses on one judge, Sir Egbert Udo Udoma of Nigeria, who served as Uganda’s first African chief justice and later as an influential member of the Nigerian Supreme Court. Udoma and others like him traversed the continent in the name of African cooperation, making a new body of law as they did so. Their rulings were portable, and they came to underpin military rule in many states, both in Africa and in the wider Commonwealth.