A transplant from a Deep South State: Thurmond ran a single-issue campaign focused on protecting racial segregation in the Deep South, and his explicit strategy was never to win but to force the election to the House where he could extract concessions from either Truman or Dewey. North Dakota didn't have Jim Crow, so North Dakotans would have had no reason to vote for Thurmond even if they were racist. People who try to claim otherwise (such as Trent Lott in his infamous 2002 flap where he said if Thurmond had won, "we wouldn't have had all these problems over all these years" and then tried to claim he was talking about Communism and the Korean War) are engaging in historical revisionism, much like people who claim the Civil War was about States' Rights. And with similar motivations.
I don't doubt that this is generally correct. However, 374 votes just seems like too many to have
all been all cast by Southern transplants in North Dakota in 1948.
I imagine that, because of Truman's broad unpopularity in 1948, at least some (greater than zero) of the 374 Thurmond votes could have been from conservative-leaning and/or low-information Democratic-leaning voters, who didn't want to vote for Truman but weren't open to voting Republican, and so voted for Thurmond either because Thurmond was the only candidate besides Truman with the word "Democratic" next to his name on the ballot (although sources seem to indicate he was listed as the "States Rights" rather than the "States Rights Democratic" candidate on the ND ballot), because Thurmond was the only nationally prominent incumbent Democratic politician on the ballot besides Truman (Wallace had not been incumbent for four years), and/or because they saw the Wallace-Taylor ticket as being too radical/heterodox.
