Bernie Sanders is almost twice as popular as his rival for the Democratic nomination, Hillary Clinton, in West Virginia. Among likely Democratic primary voters, the firebrand senator from Vermont leads Clinton 57% to 29%, according to a new poll.

As far as Sanders' prospects for snagging the nomination are concerned, his potential landslide there isn't particularly important. The primary there isn't until May 10, it's a small state with a modest share of delegates, and there's a good chance that the upcoming primaries over the next few weeks will allow Clinton to develop an insurmountable lead in the delegate count over Sanders well before April.

The fact that Sanders is well-liked in West Virginia isn't something that his nomination odds will ever hinge on, but the phenomenon is still of serious significance for Democratic Party operators. His favorability in that patch of Appalachia is the latest sign of an emerging trend: His consistent ability to capture the imagination of white working class voters — a demographic that has shown relatively little interest in Clinton so far this cycle and shunned President Barack Obama at historic rates in election cycles past.

It's also a part of the Democratic electorate that's particularly vulnerable to Republican frontrunner Donald Trump, whose populist air and aggressive push for protectionist economic policy is something that appeals to working-class voters — including those who affiliate with organized labor and tend to vote Democratic.

Regardless of whether Sanders clinches the nomination, his candidacy represents a departure from the way popular Democrats have been doing business for quite some time. The party has been drifting away from considering labor unions and the economic principles that underlie their grievances and policy visions for decades. Sanders represents an opportunity to expand the Democrats' base among a group of people who, should they continue to not feel particularly inspired by a Clinton nomination, could end up staying at home or casting their ballot for a Republican like Trump in November.

Getty Images

The trend: Early on in the race last year, many political analysts believed that if Sanders was to pose a serious challenge to Clinton, one of his core constituencies would end up being affluent and educated white voters, who were essential to Obama's rise in 2008. But it's become clear that Sanders' special strength lies in his appeal to the less educated and lower-income whites. In Iowa, Sanders' won white voters with incomes less than $50,000 a year by a margin of 9 points. Clinton, by contrast, did best against Sanders among the richest voters. In New Hampshire, one of the whitest states in the country, Sanders destroyed Clinton 71% to 25% among voters making less than $30,000. In Nevada, Sanders won non-college educated white voters by nearly 10 points.

Nationally, the trend is also clear. "In a compilation of New York Times/CBS News surveys since November, Mr. Sanders leads Mrs. Clinton, 47 percent to 39 percent, among white voters who make less than $50,000," reported the New York Times in January. "If anything, these figures may understate Mr. Sanders's strength; he has gained in state, national and New York Times/CBS News surveys over the period."

Sanders' West Virginia popularity is also a useful bellwether. Back in 2008, former North Carolina Sen. John Edwards won 7% of the vote in the state's Democratic primary — months after he dropped out of the race. It's a state that seems to be particularly fond of white populists.

The reason this is particularly remarkable is that in 2008, it was Clinton who did better among working-class whites. While Obama was favored among wine-track whites, Clinton generally trounced Obama among working-class whites. Her command of that demographic was seen as a sign that the group skewed more moderate and was more inclined toward an establishment candidate.

But so far, Sanders is shattering that assumption. He's demonstrating someone can be an outsider who has only recently arrived on the national scene, identify as a democratic socialist, speak with fervor about class warfare and still win the affection of working-class whites in astonishing numbers.

If Sanders wins the nomination, whether or not he'd be able to make a serious dent in Republican dominance among working-class whites is still an open question. Generating excitement is one thing, mobilizing people for votes is another. But so far he does appear to be the best-suited Democratic candidate in a long time to snag this key Republican constituency.

If Clinton wins the nomination, she'd be wise to position herself to bring Sanders' lower-income following into the fold. As John Nichols reported in the Nation, union leaders have found internal polls showing an unusual amount of interest in Trump. AFL-CIO president Richard Trumka said workers are "talking to me about Donald Trump," and Service Employees International Union president Mary Kay Henry has expressed serious concern that he could win a non-trivial amount of the union vote if he runs in the general election. Trump's fiery anti-establishment rhetoric and his commitment to keeping jobs within the U.S. is striking a chord with people who work in sectors that have been ravaged by globalization, in a manner that transcends traditional political divides.

Even if liberal-leaning, working-class whites don't end up crossing the aisle to vote for Trump, their disappointment with Sanders dropping out of the race could dampen their overall enthusiasm and keep them at home on Election Day — also a bad scenario for Democrats. If Clinton runs in the general election, she needs to find a way to channel the enthusiasm that Sanders' candidacy has generated.

That would be a challenge, but also an opportunity. Working-class whites constitute a smaller share of the electorate than they ever have in modern politics, but they're still a key voting demographic and one that many establishment Democratic strategists have assumed to be a lost cause for quite some time. If Sanders has taught us anything, it's that assumptions should be tested.

Get the five stories that will challenge you to rethink the world by signing up for MicCheck Daily.