Countless pixels have been expended on the Democrats’ “midterm drop-off problem,” in which core Democratic groups such as young voters, minorities and single women are expected to go to the polls in lower percentages than GOP groups, putting Dem control of the Senate in peril.

What if a key part of the problem is that many of these voters simply don’t know that Democratic control of the Senate is at stake in this fall’s elections?

That’s one of the conclusions veteran Dem pollster Celinda Lake reached after conducting new focus groups and polling for the liberal group MoveOn. Lake conducted two focus groups of people from Detroit and its suburbs. One was made up of single white women under 55 and married white women under 35 (millenials). The second was all African American women. These are the same voters who are expected to drop off in many red state Senate contests, too.

“We were exploring what would motivate them to turn out to vote,” Lake tells me. “One of the things that came up is that these drop-off voters had no idea that control of the Senate was even up for grabs and were even very confused about who controlled it. These voters are very representative of drop-off voters in a lot of states.”

Lake says the focus groups — and follow-up polling Lake conducted — determined that one message that motivates these voters is that the outcome of the Senate election in their state could decide Senate control. However, that alone isn’t enough to motivate these voters. They also need to be told why it should matter to them which party controls the Senate, Lake adds.

To determine what messages might work, Lake surveyed 1,000 “low propensity” Dem voters from North Carolina, Colorado, Iowa, Michigan, and Kentucky. These folks voted in 2012 but didn’t vote in 2010 and expressed little interest in voting in 2014. MoveOn’s polling memo summarizes some of the key messages about potential GOP control of the Senate that move them:

Should the GOP take control of the Senate, drop-off voters are most concerned that “Republicans will take away a woman’s right to choose and restrict access to birth control” (58 percent rank this very concerning), “Republicans will cut access to health care for 8 million people and let insurance companies refuse to cover people with pre-existing conditions” (58 percent) and “Republicans will cut back workplace protections for women, denying equal pay for equal work” (57 percent)….

The top testing message overall emphasizes education, specifically Republicans’ efforts to cut programs for students while giving tax cuts to the wealthy (54 percent very convincing). This message is the strongest argument for coming out to vote in all of the states except Colorado…the message focusing on Republicans’ war on women is the second strongest in all states besides Colorado.

Variations of all these messages are being employed in many of these tough races.

What all of this indicates, Lake notes, is that Democrats cannot hold the Senate through persuasion alone. It isn’t just that turnout will be key. It’s that much of the substantive messaging — in addition to traditional organizing — is also focused specifically on boosting turnout among core Dem groups.

“There is no one message or one approach that works,” Lake says. “Efforts have to be integrated. If I am going to get this voter, he or she has to get a phone call, and then see a banner ad on line, and then the week before early voting starts they get a post card.” But even that isn’t enough, Lake says: They need to be told GOP control of the Senate is a real possibility, as well as “what difference it’s going to make for your family.”

Of course, Democrats are already spending huge money on such efforts. The DSCC’s Bannock Street Project is investing $60 million in organizing that is premised on contacting voters again, and again, and again. Dems are bringing unprecedented levels of organizing to states that aren’t contested in presidential years, such as Arkansas.

Dems may end up losing the Senate, but along the way, they will have spent more resources and time on trying to solve this “midterm drop-off problem” than ever.

There are a confluence of reasons for this emphasis: The Obama campaign’s innovations in data and voter outreach. The shock of the 2010 loss. The awful 2014 Senate map for Dems, in which control of the Senate is being decided in seven states won by Mitt Romney. And on top of all that there’s the impact of shifting demographics on the two parties’ coalitions.

“Every year Democrats come to rely more and more on people who have less of a regular voting history,” Lake says. “As the coalitions are changing, Republicans are relying more and more on older, whiter voters. We’re relying more and more on voters who have irregular turnout.”

All of which is another way of saying that the problem isn’t going away.