Why did Dayton win? In a nutshell, the Peoples Republics of Minneapolis, St. Paul, and Duluth.
[Pioneer Press] “. . .While Republicans were retaking the House, Dayton defeated Republican challenger Jeff Johnson, 50-45 percent, by piling up huge vote margins in the state's three largest DFL strongholds: Hennepin, Ramsey and St. Louis counties.
"Johnson carried most of the state's suburban and rural counties, but Dayton beat him 63-22 percent in Ramsey County, 62-32 percent in St. Louis County and 59-36 percent in Hennepin. The governor won by 110,000 votes because he carried those three counties by 185,000 votes."
One difference between Northern tier states like Minnesota and New York and the South is that rural, predominantly white areas vote 55-60% Republican, whereas similar areas in Southern states vote 75-90% Republican. In one Texas Panhandle county, the Democrat U.S. Senate candidate received 3.5% of the vote, barely beating the Libertarian candidate, who got 2.5%. Additionally, while the core counties in Southern states are liberal, the suburban counties are not. (I exclude the Northern Virginia and south Florida metro areas, which are Northeastern/Caribbean colonies.) OTOH, most of the suburban counties around New York City went Democrat, though by lesser margins than the city proper.
Even in darkest Yankeeland, there is a glimmer of hope, in the three "M" states in that region electing Republican (though RINO) governors.