The voting gap likely to define the 2014 midterms

A voter casts her ballot at a polling site during early voting for Georgia's primary election in Atlanta on May, 16, 2014.
A voter casts her ballot at a polling site during early voting for Georgia's primary election in Atlanta on May, 16, 2014.
When election watchers keep an eye on the polls, they're right to focus on the attitudes of likely voters, not registered voters. After all, those who want to know who's favored to win need to study the attitudes of voters who actually plan to participate in the election.
But on the eve of Election Day, it's worth pausing to note the gap that may ultimately define the cycle, at least as far as Democrats are concerned: the gap between likely voters and registered voters will probably make the difference between victory and defeat.
This jumped out at me in the new NBC/Wall Street Journal poll.

Republicans and Democrats are deadlocked heading into Election Day, with 46 percent of likely voters preferring a Republican-controlled Congress, and 45 percent wanting a Democratic-controlled one, according to the final national NBC News/Wall Street Journal poll before the election. [...] Among the larger universe of all registered voters in this new NBC/WSJ poll, Democrats hold a four-point edge in congressional preference, 46 percent to 42 percent, which is unchanged from last month.

Washington Post/ABC poll published last week found similar results: among registered voters, Democrats led Republicans by three points; among likely voters, Republican led Democrats by six points.
This gap may not sound like much, but in a cycle like this, it's everything -- Americans this year prefer Democrats; Americans who actually intend to show up prefer Republicans.
This is evident in statewide polling, too. On Friday, CNN's latest surveys found Bruce Braley (D) leading by six points in Iowa's U.S. Senate race among registered voters, but he trailed Joni Ernst by two points among likely voters. In North Carolina, Kay Hagan (D) leads by two points among likely voters, but that margin grows to a far-more-comfortable six points among registered voters.
In other words, pretty much everywhere we look, with precious few exceptions, we see Democrats running into the same dynamic party leaders find so excruciating: Republicans get engaged in midterms, Democrats stay on the sidelines, and the consequences are severe. It happened in 2010 and it appears to be happening again in 2014.
Democratic officials are all too aware of the problem. Indeed, viewers may have seen Rachel's segment last week from Denver, home to the "Bannock Street Project," created in part to address this recurring party problem.
But the available data suggests those efforts may be coming up short. Democrats may take some solace in knowing they're winning the broader argument -- the country at large prefers their candidates and policies -- but the goal is to win the elections. And there's strong evidence right now that Republicans have the advantage with those who intend to stand up and be counted.
Postscript: Making matters slightly more exasperating for Democrats, their lead would be even larger still among all Americans, but many of their likely backers don't register at all.