How do states acquire sovereignty?

By the recognition of their citizens. (and by acceptance by other sovereign nations) In the US, states originally acquired sovereignty as recognized under the Articles of Confederation (1777) and the Constitution (1781). Later states, beginning with Ohio, established their authority under the Enabling Act of 1802 (based on the Northwest Ordinance of July 13, 1787). It should be noted that states are granted powers under the Constitution that they themselves ratified, on behalf of their citizens. In a democracy, the ultimate sovereignty lies with the people.