For two decades, Democrats relied on a seemingly impregnable blue wall in presidential elections.

The 18 states plus the District of Columbia that voted for a Democratic presidential nominee in six consecutive elections afforded the party 90 percent of the electoral votes needed to win the White House. Successive Republican campaigns tried and failed to make inroads into that wall, but repeatedly fell short. Even George W. Bush couldn’t break through in any of the states.

Then, last November, three big Midwestern bricks came tumbling down.

ADVERTISEMENT

Trump even came within 45,000 votes of winning Minnesota, a state that hasn’t voted for a Republican presidential candidate since 1972 — the longest such Democratic streak in the nation.

The Democratic collapse in the Upper Midwest was no Republican tsunami, a one-time fluke disaster from which the party would easily rebuild. Instead, it was a red tide, sweeping a specific kind of white working-class voter away from Democrats and onto GOP shores beginning as early as 2010.

“The Midwest is ground zero here,” said Matt Canter, a Democratic pollster who hails from Wisconsin. After years of taking those states for granted, “the math doesn’t work in these states without winning large swaths of white voters.”

This is the 19th story in The Hill’s Changing America series, in which we examine the demographic and economic trends influencing American politics today.

Democrats who relied on the diverse coalition Obama put together in 2008 and 2012 were uniquely susceptible to that coalition’s collapse in the Upper Midwest. Those states are more likely to be whiter, older and less educated than the national average, all factors that correlate with conservative voting patterns.

And those older, whiter, blue-collar workers have felt the stresses of a recession devastating to the manufacturing sector like no other group in America.

Even before the recession, major industries that drive the Midwestern economy had began to change.

In 1950, 39 percent of Michiganders worked in the manufacturing sector, about twice the national average. By the 1970s, the energy crisis sent automakers into a tailspin, one that forced them to streamline their assembly lines and take advantage of new technology to cut costs — and employees.

Those technological advances have cost more jobs than other factors like globalization, regulations and even recessions. There are now more industrial robots per worker in auto-heavy metropolitan areas like Youngstown and Toledo in Ohio and Detroit and Grand Rapids in Michigan than any other major city, according to an analysis by the Brookings Institution’s Metropolitan Policy Program.

(Automation is likely to cost many thousands more jobs in the future: The nation’s three largest automakers are investing more than $21 billion on plant renovation, which likely means more robots and fewer jobs down the line.)

Mining in northern counties in Minnesota, Wisconsin and Michigan’s Upper Peninsula has followed a similar path of technological innovation and economic decline.

“We really did have thriving industrial economies from Buffalo and Pittsburgh in the east through St. Louis,” said Reynolds Farley, a professor emeritus of sociology at the University of Michigan’s Gerald R. Ford School of Public Policy. “Many of those jobs can be, and have been, automated.”

Even the farming sector that employed so many thousands of Midwesterners, and which largely survived the global recession thanks to high commodity prices, has gone through an automation revolution.

“[Agriculture] as a whole has really come on some tough times again. Prices are down, even though yields are good. Making a profit is difficult,” said Gary Hendrickx, a commissioner in Swift County, Minn.

The economic stresses of a changing job market has caused a rapid migration of younger and more mobile workers away from rural areas around the Upper Midwest. Michigan’s Upper Peninsula has fewer residents now than it did in 1910, Farley said. Detroit's population today is just more than a third of its peak, in 1950. Minnesota’s Iron Range has a smaller population than it did in the 1960s.

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 Reps. 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 George Washington University.

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

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.

Similarly, Obama won 45,000 more votes than Clinton did in Milwaukee County, Wis., almost twice Trump’s statewide margin there.

The decline in minority and younger voter turnout has validated Republicans who suggested over the years that Obama’s success was unique to his campaign and that Democrats have yet to figure out how to inspire those voters absent the charismatic former president.

Said Tim Saler, a Republican data analytics expert who has worked in the Upper Midwest: “There is such a thing as a presidential-only Democrat voter.”

Democrats just haven't figured out how to turn those voters out if Obama isn't on the ballot.