The Hill, a national publication based in Washington D.C., has another yet explanation of how President Donald Trump won Wisconsin. Underlying economic changes combined with white working-class anger directed at the incumbent administration of President Barack Obama helped build Trump’s margin of victory:

Even with population declines and economic anxiety, Democrats held their own across the Upper Midwest, until Obama won office. Two years later, long-time Democratic members of Congress David Obey (Wis.), Bart Stupak (Mich.) and Jim Oberstar (Minn.) left office, either having lost or retired.

At the same time, Republicans won the governorships of Wisconsin, Michigan, Iowa, Ohio and Pennsylvania.

In 2016, white working-class voters abandoned Democrats at a greater rate in those states than anywhere else in the country, according to Robert Griffin, a demographer at the Center for American Progress and the George Washington University.

That shift took a deep political toll on Democrats: In 2012, Barack Obama won 167 counties in Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio and Wisconsin. In 2016, Donald Trump won 110 of those counties.

But while white working-class voters were abandoning the Democratic Party, the absence of Obama on the ballot drove down minority voter turnout.

Democrats were also stung by their inability to turn out core voters who gave Obama such a boost in 2008 and 2012. African American turnout plunged by 12 percent in Ohio and by 34 percent in Wisconsin. Turnout among those between the ages of 18 and 29 dropped by more than a quarter in Wisconsin, and by a fifth in Ohio, according to an analysis compiled by the Democratic data analytics expert Tom Bonier.

The effect of Obama’s absence from the ballot was especially strong in Milwaukee. Obama won Milwaukee County by 45,000 more votes than Hillary Clinton’s margin of victory there, almost double Trump’s statewide margin.

The analysis by the Hill shows just how difficult the Democrats’ task will be to try to unseat Governor Scott Walker who will be running at a time of record low unemployment, fiscal stability and a weak Democratic field.