How did the united states govern puerto rico?

The United States acquired control over Puerto Rico following the Spanish-American War in 1898 as part of the Treaty of Paris which ended the war. In this treaty negotiated between Spain and the United States the last remaining territories of the Spanish Empire were either granted independence (the case of Cuba) or were ceded over to American control (the case of the Phillippines, Guam and Puerto Rico).

lincoln declared that slavery should not be allowed to spread into the new states, and of course this angered the south at the time.