Michael Barone‘s latest Washington Examiner article dissects new data associated with voters’ support for the two major parties.

The Democratic party identification edge has been reduced to 47 to 43 percent. That’s a 4-point drop for Democrats and a 4-point rise for Republicans since 2008.

The Pew analysts note, as if they were analyzing a growth stock, that the Republicans’ numbers haven’t improved since 2010. But the 2010 numbers yielded a 52 to 45 percent Republican lead in the popular vote for the House.

If — and it’s always a big if — Republicans can maintain that standing in party identification, they should be in fine shape in November 2012, even with increased presidential year turnout.

It’s interesting to see which groups have moved most in party identification.

As the Pew analysts note, there has been little change among blacks, who are overwhelmingly Democratic. Hispanics come in at 64 to 22 percent Democratic, somewhat better for the president’s party than last year, when they voted 60 to 38 percent Democratic in House elections.

But there has been big movement among whites. In 2008 they were 51 to 40 percent Republican. In the first half of 2011 they were 56 to 35 percent Republican — more Republican than Southern whites were three years ago.

The most noteworthy movement among whites has been among voters under 30, the so-called Millennial generation. Millennials voted 66 to 32 percent for Barack Obama in 2008 and identified as Democrats rather than Republicans by a 60 to 32 percent margin.

But white Millennials have been moving away from the Democrats. The Democratic edge in party identification among white Millennials dropped from 7 points in 2008 to 3 points in 2009 to a 1-point Republican edge in 2010 and an 11-point Republican lead in 2011.

There have been shifts of similar magnitude among whites who are low-income, who have no more than a high school education, and who live in the Midwest.