Why is a state unlikely to be both a confederation and dictatorship?

Because confederations are by definition decentralized states, and dictatorships need centralized power.

Explanation:

Confederations are voluntary unions of federal member states that hold some degree of autonomy. A good example of a confederation is Switzerland, which emerged in the MIddle Ages, and currently has 24 member cantons.

Dictatorships are rare in confederations because dictators need to hold a lot of powers to be effective. A dictator of a confederation would likely attack the autonomy of the federated states, changing the nature of the confederation itself.

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