Democratic nominee Scott Colom has defeated Republican Sen. Cindy Hyde-Smith in Mississippi’s closely contested U.S. Senate race after a prolonged ballot counting process, giving the state its first Black U.S. senator since post-Civil War Reconstruction.

Colom’s narrow victory is a seismic shift in Mississippi, which has been controlled mostly by white conservatives for generations, and it will echo through the country as well. The outcome adds to a decisive midterm rebuke of President Donald Trump, whose party suffered defeats in several Republican-controlled states, and it will bolster some Democrats’ argument that their future runs through the American South.