Sen. Bernie Sanders addresses the Democratic National Convention in Philadelphia on July 25. (Toni L. Sandys/The Washington Post)

Aroostook County occupies the northernmost tip of Maine. It is vast and rural, and less than one-fifth of its adults graduated from college. It is hundreds of miles removed from the industrial Midwest, and yet a good place to start probing the question of how Democrats could win back the "Blue Wall" states that crumbled behind Hillary Clinton and cost her the presidency.

On Election Day, Aroostook County voted for Donald Trump over Clinton by 17 percentage points, helping to deliver the Republican nominee an electoral vote from the state's 2nd Congressional District. It also, by a seven-point margin, voted to raise Maine's minimum wage to $12 an hour. Trump only out-polled the minimum wage increase by 400 votes.

From that data point, and dozens of others mined from the results of the Nov. 8 vote, it's tempting to conclude that economic populism alone could lead Democrats out of political wilderness and back to the White House in 2020. This is the argument of a number of Democratic strategists and policymakers, including Democratic pollster Stan Greenberg and Sen. Bernie Sanders.

"You cannot take this election as anything but a mandate for bold economic changes to rewrite the rules of the economy," Greenberg wrote in an analysis of post-election polling. Sanders, meanwhile, has told GQ: "You need to stand for something! It’s not good enough to say, 'Well, I’m not a racist, I’m not a sexist, I’m not a xenophobe, I’m not a homophobe, you gotta vote for me.'”

Yet upon detailed inspection, the failure of the Clinton campaign to advance an adequately populist message only partially explains her loss — and thus might not be an adequate prescription for the party's next steps.

The case for populism

For certain, economically battered white workers in the industrial Midwest turned against Clinton en masse and delivered victory to Trump. A strong, worker-focused message is likely a crucial part of either party winning the presidency in an era of declining middle class fortunes.

The prescription for Democrats starts by accepting that a huge swing in key states among white voters without a college degree — away from past support of President Obama, and toward Trump— cost Clinton the electoral college. That's clear from a wealth of election autopsies, including a detailed analysis of election returns by Civis Analytics, a political data firm founded by the chief analytics officer of Obama's 2012 re-election campaign (which did not do any work for Clinton this cycle.)

The Civis analysis explored how Clinton lost the race via narrow defeats in three states that had previously been part of the vaunted "Blue Wall" for Democrats: Wisconsin, Michigan and Pennsylvania. In each, it found a tight relationship between lower education levels in a county and an erosion in Democratic support from 2012.

Source: Civis Analytics

"The story is simple — it’s not about turnout, it’s about support, specifically among white non-college voters," said Dan Wagner, the founder and chief executive of Civis. "In majority white counties where more than 20 percent of the population went to college, support dropped by about a point and a half. In majority white counties where less than 20 percent of the population went to college, support dropped by nine points. If this drop had only been five points, Hillary would have won Pennsylvania, Michigan and Wisconsin, and the presidency."

This is where Aroostook County is illustrative. It was filled with the sort of non-college-educated white voters Clinton saw break away from her and toward Trump — and it shows a clear appetite among those voters for a populist economic pitch, in raising the minimum wage.

Maine was one of several states targeted this year by a group of progressives seeking to raise minimum wages by referendum. Voters there approved an increase to $12 an hour by 2020, as did voters in Arizona and Colorado.

But populism is only part of the story

So yes, if Democrats want to rebuild their "Blue Wall" in the Midwest, they need to win over a lot more white voters without college degrees. For starters, they'll have to show up more often. Clinton never set foot in Wisconsin during the general election. She barely went to Michigan and only began advertising there late. She abandoned her economic pitch on the airwaves late in the race, instead going all-in on attempts to paint Trump as unfit for the office.

In the closing weeks of the campaign, the Political TV Ad Archive counted 12,723 advertisements aired by the Clinton campaign in a quartet of battleground markets: Cedar Rapids, Iowa; Cleveland; Milwaukee; and Philadelphia. Only 769 of those ads — 6 percent — focused even in part on the issue of "jobs," the Archive found. By contrast, Trump focused on jobs in 43 percent of his ads — a total of 3,086 spots.

Yet even this is likely to be inadequate — for at least three reasons.

1) Clinton lost Pennsylvania, a state she showered in ads and in attention, including her own campaign stops and trips from the party's favorite Scranton surrogate, Vice President Biden. She lost Ohio by a much larger margin, despite heaping ads and attention on the state.

2) A true economic populist Democrat, Russ Feingold, lost his Senate race in Wisconsin — by a wider margin than Clinton did, and against a far less populist opponent than Trump. Feingold earned fewer votes in Wisconsin than Clinton did.

3) Economics wasn't the only force driving this election. There is evidence that racial factors help explain the big shift in blue-collar whites toward Trump, whose campaign often stoked tensions over immigration and refugees. These factors  accompany economic forces in the assessments of why Democrats lost this year.

Taken together, those points cast doubt on the idea that Clinton would have held the Blue Wall simply by talking louder and more often about how the economy is "rigged" against workers and in favor of the rich and the powerful.

Looking toward 2020, the danger of betting on complaints about a "rigged" economy is that Democrats can't be sure how rigged things will appear to Midwestern voters in four years. As I wrote last week, Trump inherits an economy where middle-class incomes have begun to rise, and if he can keep it on that course, his first term will see meaningful improvements to those workers' lives.

It will be a much larger challenge for Trump to deliver the industrial revival he promised those workers in the industrial Midwest — the return of millions of manufacturing and mining jobs. Most economists doubt he can deliver. If he doesn't, Democrats will have an opening — an opportunity to pitch those workers on policies that could help create jobs that pay better, but just as importantly, restore the sense of pride and ownership many of them once felt in their jobs.

As Sherrod Brown, a Democratic senator from Ohio who faces reelection in 2018, wrote following the election, those workers "know they toil harder and are paid less than their parents, and have less power to control the hours they work and their share of the wealth they create for their employer."

It probably won't be enough for the next Democratic nominee to acknowledge that sense of loss. She or he will need a plan to reverse it — one that competes with the return-to-glory promises that Trump offered this time around.

The most successful Democratic nominee among non-college white voters over the last three decades, Bill Clinton, was able to make that sort of connection — and maintain it, by steering a hot economy that delivered wage increases to workers of all races, geographies and education levels. In her run, Hillary Clinton was hindered, in part, by the failure of Bill Clinton's policies to keep delivering good jobs for the working class, particularly when it came to trade deals.

For all her white papers and all her slogans on the economy, Hillary Clinton never offered a tangible vision of what millions of new, more dignified jobs would look like; how struggling workers would find them; and what she would do, as president, to make sure those jobs sprouted in their back yards.

If you're looking for a starting point for the next Democratic nominee, that's a pretty good one.