(J. Scott Applewhite/AP)

Despite the declining job approval for congressional Republicans, Democrats may lose millions of votes from core constituents next year because so many are losing interest in politics, a new survey indicates.

Democratic pollster Celinda Lake told reporters this morning that, while there is always a dropoff in turnout for mid-term elections compared with presidential elections, this time it could be particularly harmful for the Democrats. The dropoff could "determine who will control the House [now in Republican hands] and whether we control the Senate" [now under Democratic control]," she said.

Lake noted that 53.5 per cent of the eligible voting population now consists of unmarried women, young people 18 to 29 years old, African Americans, Latinos, and "all other non-white races" which she calls the "rising American electorate." They went heavily for President Obama in 2012.

Lake's survey found that, "If past trends hold true, it is predicted that more than one in three RAE voters who turned out in 2012 will not turn out in 2014." The survey estimated that "34.5 per cent of those voters who voted in 2012, or 21.8 million RAE voters, will stay home."

The biggest dropoff is expected to be 46.8 per cent among young people, compared with 36.2 per cent among African Americans, 34.1 per cent among Latinos, and 32.9 per cent among unmarried women.

There was a 36.6 per cent dropoff in voting by these voters between 2008 and 2010, resulting in large gains for the Republicans in Congress.

Among non-RAE voters, the dropoff between 2008 and 2010 was 28.4 per cent. The estimated dropoff of these more traditional voters between 2012 and 2014 will be much lower, 17.5 per cent, or 12.2 million votes, according to Lake's research.

The survey was sponsored by the Voter Participation Center, a group that specializes in research on the voting behavior of African Americans, Latinos, unmarried women and young people.

A spokeswoman for the center said progressives should focus on issues that are of particular concern to these voters, especially economic issues, to motivate them to vote.

Ken Walsh covers the White House and politics for U.S. News. He writes the daily blog, "Ken Walsh's Washington," for usnews.com, and "The Presidency" column for the U.S. News Weekly. He is the author of the new book "Prisoners of the White House: The Isolation of America's Presidents and the Crisis of Leadership." Ken Walsh can be reached at kwalsh@usnews.com and followed on Facebook and Twitter.