A new analysis of labor data offers insight into why Donald Trump delivered surprise wins in Michigan, Wisconsin and Pennsylvania. Yes, he swept the Rust Belt. But more specifically, he won over voters in counties that were most dependent on blue-collar work — including hordes of longtime Democratic voters.

The report from Emsi, a labor market advisory firm, found nearly every Rust Belt county with a higher-than-average concentration of manufacturing, mining or agriculture jobs backed Trump, including some that had supported liberal contenders since 2000.

The numbers show a striking dominance. In the six states examined — Michigan, Ohio, Minnesota, Wisconsin, Indiana and Pennsylvania — 437 of 489 counties picked Trump.

In 93 of those counties, the share of manufacturing jobs is three times higher than the national average, according to co-author Josh Wright’s calculations.

All 93 went for Trump.

Wright, an economic modeling specialist, said areas with dense manufacturing sectors particularly pulled for Trump, perhaps because he came to represent hope for a struggling industry. Traditional manufacturing jobs in the United States have sharply declined since 2001, dropping, by his calculations, from 12 percent of the workforce to today’s 8.2 percent.

“His message struck a chord with a lot of people in that region,” Wright said. “There’s a nostalgic sense of wanting to hold onto jobs that are hard to keep in the long term.”

Wisconsin's Kenosha County, for example, has endured a 34 percent drop in manufacturing jobs since 2001 — and it broke 16 years of Democratic voting this election in favor of Trump. The state's Adams County, which experienced a 24 percent decrease in manufacturing jobs during that period, broke an identical Democratic streak. So did Luzerne County in Pennsylvania, where manufacturing employment has fallen 34 percent.

A complicated blend of automation, trade and shifting market demands sparked the decline, and the job loss hurt a Heartland version of the American dream.

“In the '60s and '70s,” Wright said, “people didn’t have to have a ton of education to get really solid-paying jobs on the factory floor.” 

These days, finding decent pay without a college degree is harder.

An area’s deepening reliance on manual labor also turned out to be strongly predictive of how it would vote. Every county in the analysis that saw growth of factory, mining or agriculture jobs over the last 15 years supported Trump.

Just two with twice the national share of such positions voted for Hillary Clinton. The Rust Belt counties that swung her way tended to have more economic diversity, or, in other words, they wouldn’t face as large of an employment crisis if a factory or two closed.

Trump promised throughout the campaign to bring back American jobs, the kind vanishing across the Rust Belt. Exit polls and interviews suggest voters believed him. The president-elect wielded his White House influence in late November, reaching a deal with Carrier, an air conditioning company, to keep 800 factory jobs earmarked for Mexico in Indiana. He has continued to apply pressure to companies across the country, particularly those in the auto industry, threatening to impose steep tariffs on firms that ship goods from south of the border.

It is unclear how the Trump administration will impact the economy, considering automation took out more U.S. manufacturing jobs over the last two decades than trade. But the voters who put him in office say they're holding him to his word.

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