New study blows up one of the central myths of Trump's presidency

Donald Trump has been widely credited with bringing white working-class voters to the polls, but there are some problems with that analysis.

The first problem is there's no universally accepted definition of "working class," and many surveys measure only broad outlines of voter income and education -- and fail to note those voters backed Republican candidates in previous elections, as well, according to political scientists Nicholas Carnes and Noam Lupu in a new column for the Washington Post.

"In our research, we often define working-class Americans as people who earn a living doing manual labor, service industry and clerical jobs," the pair wrote. "However, most major political opinion surveys don't include that kind of information about voters' occupations; instead, they report on factors like household income and education level. To study voters, we instead define the working class as people without a college degree — which many journalists focus on — who are in the bottom half of the household income distribution — since many Americans who don't finish college still go on to earn high salaries."

If working class voters are defined in that way, there's no evidence at all that Trump remade the Republican base -- and may have stalled a long-term trend of white working-class voters backing GOP candidates for the first time since 2008.

"At least since the 1980s, white working-class Americans have never made up a majority of Republican voters in presidential elections," the researchers wrote. "The share of Republicans who are white and working class has increased slightly in the last few election cycles, but not under Trump. The biggest single-year increase in the white working-class's share of GOP voters came in 2012, when Mitt Romney was the party's nominee. Since Romney, the share of white working-class people among GOP voters hasn't budged."

"Lower-income white voters without college degrees aren't a majority of Republican voters," the pair added, "and they aren't increasing as a share of GOP voters."