From the Senate to gubernatorial races, here are the key Republican winners from the 2014 midterm elections. (The Washington Post)

The most common explanation we’re hearing for the GOP sweep of a dozen Senate races last night is that an already-treacherous map for Democrats was made a lot worse by the failure of core Dem voter groups to show up.

But multiple Democratic pollsters involved in these races identify another problem: The failure of the Democrats’ economic message to win over persuadable voters, ones outside the ascendant Democratic coalition, in the numbers needed to offset the structural disadvantages Democratic incumbents and candidates faced. These pollsters describe this as a serious problem afflicting the Democratic Party that must be addressed heading into 2016.

No question, the map/turnout problem was daunting. But some evidence suggests that in some places, Democrats actually did push up turnout among core groups from 2010 levels. Democrats appear to have performed pretty well among these voters. But this wasn’t a 2012 electorate, and there just weren’t enough of them. Which leads to the related problem that John Judis points out: Democrats underperformed so badly among older voters and blue collar whites that it became impossible to make up that lost ground. This wasn’t just a turnout problem; it was a persuasion problem, too.

“We have a problem,” Democratic pollster Mark Mellman, who polled on the Kentucky Senate race, told me. “If we’re really going to expand our chances in the Senate and House, we have to appeal to a wider group than we are now.”

The exit polls show that candidates like Mark Pryor, Kay Hagan, Bruce Braley and Mark Udall lost by anywhere from large to truly massive margins among non-college whites and older voters. That’s also true of the overall national electorate. You should treat these exit polls with a grain of salt, but the pollsters I spoke to agree that this gets at a fundamental problem Democrats face.

These pollsters argued that this was above all the result of a failure to connect with these voters’ economic concerns. At the root of these concerns, Mellman says, are stagnating wages and the failure of the recovery’s gains to achieve wider, more equitable distribution. Democrats campaigned on a range of economic issues — the minimum wage, pay equity, student loan affordability, expanded pre-kindergarten education — but these didn’t cut through people’s economic anxieties, because they didn’t believe government can successfully address them.

“People are deeply suspicious that government can deliver on these problems,” Mellman says, in a reference to the voter groups that continue to elude Democrats. “And they are not wrong. We’ve been promising that government can be a tool to improve people’s economic situation for decades, and by and large, it hasn’t happened.”

Republicans were able to capitalize on the failure of Democrats to connect economically, in large part because of Obama’s unpopularity in these states, which helped ensure that the Democratic Party owned people’s economic anxieties.

“Republicans were exceptionally successful in nationalizing the election in most places, and on focusing voters’ anger and anxiety on Obama,” pollster Geoff Garin, who polled in the Iowa race, told me. “Voters were particularly inclined to punish whoever is running things. Democrats owned the status quo in voters’ minds.”

This dynamic fed into the broader Republican strategy of seizing on every crisis that came along to sow doubts about Obama’s — and government’s — competence. Pollster Andrew Maxfield, who polled in the Arkansas and Alaska Senate races, says Republicans successfully made the case that government just wasn’t working for people — economically or otherwise.

“This election — like 2006 — was in large part about accountability,” Maxfield says. “It became a referendum on perceived government incompetence. ISIS, Ebola, and the border fit squarely in there but it wasn’t exclusively about competence. It was also about who government is working for economically. Linking specific Democrats to Obama became a catch-all for that broader case.”

Ultimately, stressing individual issues such as the minimum wage hike and pay equity wasn’t enough to get past that — even if they are quite popular — because these voters want to hear a more comprehensive message about how Democrats would move the economy forward. Pollster Celinda Lake, who polled on multiple races, says the broader failure to articulate this — from the President on down — led these voters to opt instead for vague promises of a change in direction.

“We have a huge problem: People do not think the recovery has affected them, and this is particularly true of blue collar white voters,” Lake said. “What is the Democratic economic platform for guaranteeing a chance at prosperity for everyone? Voters can’t articulate it. In the absence of that, you vote for change.”

“Our number one imperative for 2016,” Lake concluded, “is to articulate a clear economic vision to get this country going again.”