Answer:
smaller political units maintaining their sovereignty
Step-by-step explanation:
Confederation is the name given to a country that is a federation, but the states that make up that country maintain their sovereignty, separate from the power of the federal government. In this case, to maintain a confederation it is essential that the smaller political units, the states, maintain their sovereignty. This is different from a federation, because in a federation, states lose sovereignty, transferring it to the federal government.