PRINCETON, NJ -- For several days, nationwide Democratic voters' preferences have been shifting toward Barack Obama in Gallup Poll Daily election tracking. Now, the Illinois senator enjoys his first statistically significant lead, 49% to 42%, over Hillary Clinton, according to the Feb. 13-15 results. Additionally, the 49% support for Obama represents the high point for him in the daily tracking program.

Obama has won the last eight Democratic primaries or caucuses, and hopes to make it 10 straight on Tuesday in Wisconsin and Hawaii. The tracking data reflect the Obama momentum since the Feb. 5 Super Tuesday primaries, moving from a +13 Clinton advantage in Feb. 3-5 polling to a +7 Obama lead in the latest results.

John McCain continues to be the choice of the majority of Republican voters nationwide. Fifty-four percent name McCain as their preferred nominee, with 28% choosing Mike Huckabee. McCain's support has been above 50% since the Feb.6-8 tracking results, roughly coinciding with Mitt Romney's exit from the campaign. -- Jeff Jones

Methodology: The results reported here are based on combined data from Feb. 13-15, 2008, including interviews with 999 Republican and Republican-leaning voters, and 1,223 Democratic and Democratic-leaning voters. For results based on these samples, the maximum margin of sampling error is ±3 percentage points. In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.