Republicans have taken a four-point lead in the generic ballot test with a year to go until the 2010 midterms, according to Gallup. They lead 48-44 in the poll, taken Nov. 5-8.

If you look at the total numbers in the Gallup poll, you recognize that they have polled Republicans higher in the generic ballot test than other polls out there. Seven other polling organizations who have taken polls in the last month show Democrats in the lead, and only Rasmussen tracks with a Republican lead in the generic ballot.

The lead comes entirely from a shift among independent voters, who now favor Republicans 52-30; this subset was tied in July. Since Democrats and Republicans are monolithic in their support of their party in the poll, this huge lead tips the scale to Republicans. It also means that independents either weren’t very large in the sample, or more Democrats were polled than Republicans, since that 22-point lead among indies translated into a 4-point lead overall.

Gallup writes:

The overall results would predict a likely strong Republican showing if the House elections were held today. Though the registered-voter results reported here speak to the preferences of all eligible voters, voter turnout is crucial in determining the final outcome of midterm elections. Gallup will not begin to model likely turnout until much closer to the 2010 elections, but given that Republicans usually have a turnout advantage, if normal turnout patterns prevail in the coming election, prospects for a good Democratic showing appear slim. Of course, the elections are still nearly 12 months away and conditions could shift back in the Democrats’ favor over this time.

The poll was taken right in the wake of Republican victories in elections in Virginia and New Jersey, so I wouldn’t be surprised by a “bandwagon” effect at work here. However, the real insight from those elections is that depressed Democratic turnout is fatal. I wrote several weeks ago about Womens Voices Womens Vote and the “rising American electorate,” comprised of voters aged 18-29, unmarried women, and people of color (African-American, Latino, API). WVWV has run the numbers on the New Jersey and Virginia electorates, and it’s not pretty:

So let’s go back to the VA and NJ numbers. In VA in 2008, the percentage of voters in that Rising American Electorate group was 45%. In the 2009 VA electorate, the RAE % dropped to 36%. In NJ in 2008, the % of the electorate that was in the RAE category was 49%, whereas in 2009 it was only 39%. These RAE voters didn’t come out to vote because they were discouraged that Democrats that they had invested their faith in weren’t delivering tangible benefits for their lives.

The Democrats in marginal districts who are patting themselves on the back for taking the “safe” vote by voting no on health care reform are fooling themselves, and in a great many cases dooming themselves in the next election. If the part of the electorate that strongly favors you drops by 10% (or more) in the next election, do you really think you can win a competitive race? And does not helping your party and your President deliver health reform help you or hurt you in turning out the Democratic vote? I’ll let the geniuses advising these members of Congress to vote no try to explain that one.

(The numbers from that WVWV-commissioned poll, put together by Greenberg Quinlan Rosner Research, can be found here)

As I said, Gallup tends to be favoring Republicans slightly relative to other polls. But given that Gallup only polled registered voters, this RAE drop isn’t even factored into their numbers. If Democrats can get make a tangible difference over the next 12 months, particularly by passing health care, they can possibly reverse this trend. But, time is running out.