Coinciding with the relentless broadcasting of controversial sermons by Barack Obama's former minister, Hillary Rodham Clinton has taken a slight lead over her Democratic rival in a major nationwide tracking poll.

The latest Gallup Poll Daily shows Clinton with a 5 percentage point lead over Obama, 48-43 percent, among Democratic voters.

Gallup said it marked the second consecutive day of Clinton showing a statistically significant lead over Obama since Feb. 7-9.

Gallup said its "tracking data over the next several days will be a crucial indicator of the lasting impact, if any, of the Wright controversy."

The Rasmussen Reports daily Presidential Tracking Poll showed Obama leading Clinton 46-43 percent, but in the wake of the controversy, Obama has lost ground against Republican challenger John McCain.

Obama made a major speech on Tuesday on race and American politics, and appealed for voters to move past the issue, after video clips of incendiary sermons by the Rev. Jeremiah Wright were put in heavy rotation on cable news shows, and spread via the Internet.

The week before old clips of Wright began circulating, Obama and McCain were more or less tied in the Rasmussen poll. McCain now leads Obama by 7 percentage points, 49-42 percent, Rasmussen said.