Perhaps the report of a general retreat on party affiliation was a bit exaggerated — at least for one of the two parties.  Rasmussen’s latest monthly survey of 15,000 respondents for party affiliation shows Republicans gaining more than a percentage point from November to December and nearing the year-long high, while Democrats declined to the lowest level in the Rasmussen series:

The number of Republicans in the country increased by a percentage point in December, while the number of Democrats fell back two points to the lowest level ever recorded by Rasmussen Reports.

During December, 35.4% of Americans considered themselves Republicans. That’s up from 34.3% in November and just below the high for the year of 35.6% reached in May.

At the same time, just 32.7% of adults said they were Democrats, down from 34.9% in November. The previous low for Democrats was 33.0% in August of this year.

As with the USA Today report, independents grew fastest in December, going up 1.2 points from 30.8% to 32%.  The real story in this survey, though, is the growing gap between Republicans and Democrats.  The margin in December was 2.7%, the widest margin for all of 2011.  Just three years ago, as Barack Obama took office, Democrats had an eight-point edge in affiliation, 41/33.  The new level for Republican affiliation breaks out of the long-held 31-34% range for Republicans.

Most of the GOP gain has come through subtraction, of course.  Democrats have lost more than eight points, while Republicans have only gained 2.4 points, so the movement hasn’t been from Democrat to Republican.  It looks more like Democrat to independent, with a smaller migration from independent to Republican.  There may be practical rather than ideological reasons for the shift, as I wrote with the USA Today piece.  Only one party will hold a meaningful primary process for the presidential election, which may mean that some of the GOP growth might be from people who want to participate in closed primaries in some states.  Previously affiliated Democrats may not see any advantage to staying with the party in the absence of a meaningful presidential primary, either. Still, it’s clear that Obama and his allies on Capitol Hill aren’t making much of an argument for staying inside the Democratic Party at the moment.

Nevertheless, it’s a trend that bears watching.  Rasmussen has generally tracked closely to the same trends seen in Gallup’s quarterly party-affiliation polling, so it will be interesting to see if the same trend appears there.  This will be particularly useful in analyzing general-election polling and the samples used, even if the survey itself may not lend itself to broad assumptions about the electorate’s mood.