Final answer:
A territory can regain its independence after being annexed through political and military resistance, international diplomacy, or decisions made by the imperialist country itself. The history of decolonization shows numerous instances where former colonies have become independent states.
Step-by-step explanation:
Can a territory keep its independence after an imperialist country annexed it? The answer is complex. In the history of decolonization, we have seen that territories can and have regained independence through various means. Independence can be restored through different pathways:
Political and military resistance: A territory may keep or regain its independence if it has a strong political and military response to annexation. The will of the local population to fight for independence has been a significant factor in the decolonization process.
Decisions of the imperialist country: Sometimes, the policies and strategic decisions of an imperialist power can lead to a territory being granted independence.
Throughout history, many former colonies have successfully become independent. For instance, looking at the United Nations membership, we can see that the number of independent states has increased significantly from the mid-twentieth century. This demonstrates that territories can and have regained autonomy, despite once being under imperial control.