More importantly, there is a group of Sun Belt states (Arizona, North Carolina, Georgia, and Texas) that collectively have seven Republican senators but are showing real signs of a Democratic resurgence. In Arizona, Democrats won a Senate race in 2018 for the first time since 1988, and while Mitt Romney won the state’s presidential vote in 2012 by roughly 9 percentage points, Trump only captured it by 3.5 points. Similarly, in Texas and Georgia, Trump’s margins of victory were 7 points and 3 points smaller than Romney’s. Additionally, in 2018, Democrats Beto O’Rourke and Stacey Abrams came closer to winning a Senate election in Texas and gubernatorial election in Georgia than any Democrats this century.

Demographics indicate these narrowing margins aren’t a fluke: The Cook Political Report’s David Wasserman noted that white college degree holders are the demographic trending most towards Democrats, and of the 15 states where college degree holders make up the largest percentage share of white voters, 14 routinely vote for Democrats statewide. The 15th? Texas, which ranks 12.

Wasserman offered another data point that shows why Democrats are becoming more competitive in these places: In only 11 states and the District of Columbia do large metropolitan areas cast more than two-thirds of the statewide vote. Of the 12, nine are reliably blue states, one (Nevada) has swung towards the Democrats in the last decade, and the other two are Arizona and Texas. Other research indicates that younger, left-leaning voters are flocking to Sunbelt suburbs in places like Atlanta and Charlotte, further bolstering Democrats’ hopes.