Anthills of the Savannah is definitely related to colonialism—as are most of Chinua Achebe's works. Since the novel is set in a fictional, westernized African country that is postcolonial, Anthills of the Savannah focuses on the impact of colonialism on a country after the colonizers have left.
Kangan is the fictional country where Anthills of the Savannah takes place. To understand Kangan, a reader must understand how colonization happened in Africa. European colonialism had a massive effect on modern African countries. In fact, the official languages used in some African countries come from the colonizing countries in many cases. The colonizers' social customs, political customs, and often corruption were passed on when they took over these countries—and those corruptions were exacerbated when they abruptly withdrew.
Achebe attempts to address what happens after the withdrawal in Anthills of the Savannah by focusing on three people in Kangan who all have interactions with the government, which was recently established through a military coup led by Sam, also known as "His Excellency." He writes about how society changes, the way society affects the people in it, and how power corrupts. Achebe says:
Nations . . . were fostered as much by structures as by laws and revolutions. These structures where they exist now are the pride of their nations. But everyone forgets that they were not erected by democratically-elected Prime Ministers but very frequently by rather unattractive, bloodthirsty medieval tyrants. The cathedrals of Europe, the Taj Mahal of India, the pyramids of Egypt and the stone towers of Zimbabwe were all raised on the backs of serfs, starving peasants and slaves. Our present rulers in Africa are in every sense late-flowering medieval monarchs, even the Marxists among them. Do you remember Mazrui calling Nkrumah a Stalinist Czar? Perhaps our leaders have to be that way. Perhaps they may even need to be that way.
Anthills of the Savannah is a book that centers on colonialism, even though the colonizers have left. The power vacuum and problems left in the wake of the colonizers' withdrawal create a torrent of upheaval for the characters in the novel that leads to most of the main characters' deaths by the end.
Anthills of the Savannah is about the aftermath of colonialism, which left a deep and complex legacy in Africa. Colonialism has helped to usher in many of the changes in the fictional nation of Kangan. Some, like the rampant political instability, are terrible for the people of the nation, and others, like an improved role for women, seem to be improvements. On the other hand, women also represent a link to the people's precolonial heritage, and as such are both looking forward and looking back.
But in general, the violence, instability, abuses of power, and political corruption that plague the country in Achebe's novel are direct references to similar scenarios in post colonial Nigeria, which experienced extreme civil strife (even a civil war with the breakaway people of Biafra) and kleptocratic political leadership. Achebe asks late in the book, "what must a people do to appease an embittered history?" After enduring decades of post colonial turmoil, the answer is never clear.