In their latest quarterly survey of party affiliation, Gallup gives Democrats their first piece of good news in over a year, albeit only a slender reed.  The slide in Democratic affiliation appears to have stopped, leaving Republicans within the margin of error when including leaners, 46/43.  However, since Barack Obama took office, their advantage in actual identification without leaners has also dropped into the margin of error, 32/28:

For the first time since President Barack Obama took office, the percentage of Americans identifying as Democrats or leaning Democratic held steady in a quarter’s worth of Gallup poll data. Prior to the second quarter of 2010, the percentage aligning themselves with the Democratic Party had declined at least slightly each quarter since early 2009.

With 46% of Americans identifying either as Democrats or as independents who say they lean to the Democratic Party, and 43% identifying as Republican or leaning Republican, Democrats now hold a 3 percentage-point advantage in party affiliation. The gap between the two parties had shrunk from 13 points when Obama took office to just 1 point in the first quarter of this year. That 1-point gap in the first quarter of 2010 was the smallest Gallup had recorded in five years.

The news isn’t all that good for Democrats.  They have lost ground in actual party identification and in independent leaners over the last 18 months.  The GOP has taken a slight lead among the latter, although still within the MOE.  While the Democrats gained a couple of points from the last survey overall, it came from a slight shift away from the GOP among those independents (again, within the MOE) and not any gains of their own.

Gallup notes that this means that turnout will be key — and Republicans have two advantages in the midterm on this point.  First, the GOP traditionally does better at turnout anyway.  (This poll was among the general adult population, which usually favors Democrats but does worst as a predictive model for turnout.)  More importantly, Republicans are far more enthusiastic in this midterm election than Democrats, and so are independents with antipathy towards the current Democratic leadership.  If the jobs numbers come in negative on Friday as expected, that will only increase.

This is another key indicator to remember when looking at sampling in media polling.  With leaners, Gallup found a 3-point edge for Democrats, and without leaners a 4-point edge.  Next time we see an eight- or nine-point sampling edge for Democrats (or worse), we’ll be sure to use this as a reference point.