How can one say that states retain their full sovereignty upon joining the Union when by joining, they give up the ability to choose which type of government they desire? The ability to chose a type and form of government is the first act of sovereignty. Under the constitution, this is denied to the states. The constitution states that the federal government guarantees the states a republican form of government, thus a different mode of government would be illegal. How can a body politic claim sovereignty when they cannot even choose which type of government they would like to form?