Final answer:
The efficacy of modern nation formation in relation to colonization or pre-existing cultural unity varies and is not definitive. Japan's non-colonized and culturally unified background contrasts with the challenges faced by colonized African and Asian nations. The colonizationist scheme was not universally embraced by black abolitionists.
Step-by-step explanation:
The statement that modern nations have arisen most effectively in areas that were never fully colonized or where there was already much cultural unity is complex and does not have a straightforward true or false answer. However, based on historical patterns, it can be argued that nations that either avoided full colonization or had significant cultural unity beforehand had different trajectories in nation-building than those heavily influenced by colonial powers. For instance, Japan, which was never colonized, modernized rapidly during the Meiji Restoration while maintaining a strong cultural unity. In contrast, African and Asian nations that were heavily colonized often faced challenges in state-building post-independence due to imposed borders that did not align with ethnic or cultural boundaries, often leading to conflict and weaker national identity.
Regarding the colonizationist scheme, it was not universally popular among black abolitionists. Although some supported the idea of colonization the process of establishing a colony elsewhere as a solution to racial problems in the United States, many black abolitionists opposed it, favoring the end to slavery and full civil rights within the nation.