By Reid Wilson @ TheHill.com, May 8
[....] Trump became the first Republican to win Michigan, Wisconsin and Pennsylvania in decades, in part on the strength of his performance among a handful of voters who had backed former President Obama in 2012.
Two-thirds of those Obama-Trump voters say they see Trump favorably heading into his reelection campaign — but that number has fallen by 19 percentage points since 2016, according to a new survey by the Voter Study Group.
Obama-Trump voters tend to be disproportionately located in the Midwest. They are most likely to be members of the white working class who never attained a college degree, said Robert Griffin, the Voter Study Group’s research director. Political scientist John Sides has found that about 9 percent of Obama voters chose Trump over Democratic nominee Hillary Clinton in 2016, or about 5 percent of the overall electorate. Trump won those three states by just a handful of votes — 10,704 in Michigan, 22,748 in Wisconsin, and 44,292 in Pennsylvania. The slightest erosion in support could cost him those states in 2020. “Even these shifts that look like they’re pretty small, well, the election margins were pretty small,” Griffin said [....]