According to Gallup:

In 2010, 31% of Americans identified as Democrats, down five percentage points from just two years ago and tied for the lowest annual average Gallup has measured in the last 22 years. While Democrats still outnumber Republicans by two points, the percentage identifying as independents increased to 38%, on the high end of what Gallup has measured in the last two decades

The analysis goes on to say this:

While there is usually some year-to-year variation in party identification at the aggregate level, the changes are typically not large. Thus, the five-point drop in Democratic identification over the past two years, from the party’s 22-year high of 36% (tying the 1988 figure) to its 22-year low of 31%, is notable.

Perhaps equally significant is that the percentage of Americans identifying as Republicans has increased only slightly to 29% during this time, and remains on the low end of what Gallup has measured the past two decades.

Nevertheless, 2010 was a good year for Republicans, given the party’s major gains in the midterm elections. Those gains were in part driven by the party’s appeal to independents, evident in the strong support for Republican congressional candidates among independent voters.

Independents’ increasing affinity for the GOP is also evident in a separate measure of party affiliation Gallup tracks, which takes into account the party leanings of independents. In 2010, 45% of Americans identified as Democrats or said they were independent but leaned toward the Democratic Party, while 44% identified as Republicans or said they were independent but leaned Republican. The 1-point Democratic advantage is the party’s smallest since 2003, when the parties were even, and represents a sharp decline from the record 12-point Democratic advantage in 2008.

This survey shows several things occurring at once. The most important is that after two years of President Obama and four years of Speaker Nancy Pelosi, the Democratic Party is in a very weakened state. At the same time, the nation is far from enchanted with the GOP. When it came to winning voters in 2010, the Republican Party dominated, and that counts for a lot. But the GOP “brand” remains tarnished — and, presumably, public patience with the Republican Party is limited. In addition, the high number of voters identifying themselves as independents indicates that we are seeing something of a political de-alignment occur.

All of this can change, depending on how events unfold. For now, though, the decline of the Democratic Party in the Age of Obama (and Pelosi) is among the more notable political developments of the last half-decade.