Corruption as a structural problem
Obi does not start corrupt. He resists, lectures others, and makes enemies doing it. Achebe shows corruption spreading into him gradually, driven by debt and grief. The novel frames the system itself as the problem, not just the individual.
The gap between Western education and African reality
Obi's British degree gives him ideals that do not translate. He believes in meritocracy and individual choice. His community believes in obligation and collective identity. His education widens the gap between him and the people he was supposed to serve.
Tradition versus modernity
The osu taboo sits at the center of this conflict. Obi thinks it is superstition. His parents, his community, and ultimately Clara herself know it has real social power. Achebe does not declare a winner. He shows the cost of the collision.
The burden of being a symbol
Obi is not just a man to his village. He is proof that their investment in education pays off. That symbolic weight is crushing. He cannot be broke, cannot marry the wrong woman, cannot fail. The pressure to perform success helps break him.
Grief and personal loss as catalysts
Obi's corruption does not begin with greed. It begins after Clara leaves and his mother dies in quick succession. Achebe connects emotional collapse to moral compromise. Loss does not excuse the bribery, but it explains the timing.