The highly respected Pew Research Cemter has published a new poll showing that Democrats own a decided advantage in party identification and that the gap between Democrats and Republicans in some swing states is even larger:

In 5,566 interviews with registered voters conducted by the Pew Research Center for the People & the Press during the first two months of 2008, 36% identify themselves as Democrats, and just 27% as Republicans.

The share of voters who call themselves Republicans has declined by six points since 2004, and represents, on an annualized basis, the lowest percentage of self-identified Republican voters in 16 years of polling by the Center.

The Democratic Party has also built a substantial edge among independent voters. Of the 37% who claim no party identification, 15% lean Democratic, 10% lean Republican, and 12% have no leaning either way.

By comparison, in 2004 about equal numbers of independents leaned toward both parties. When "leaners" are combined with partisans, however, the Democratic Party now holds a 14-point advantage among voters nationwide (51% Dem/lean-Dem to 37% Rep/lean-Rep), up from a three-point advantage four years ago.