PRINCETON, NJ -- Fifty percent of national Democratic voters now favor Barack Obama for the 2008 Democratic presidential nomination, compared with 42% backing Hillary Clinton.

This is according to Gallup Poll Daily tracking conducted Feb. 28 through March 1. It marks the fifth consecutive day in Gallup Poll Daily reporting that Obama has held a significant lead in national Democratic preferences.

John McCain has enjoyed solid frontrunner status in the Republican field for well over a month now. He currently leads Mike Huckabee by more than 40 percentage points, 63% to 22%. -- Lydia Saad

Methodology: Gallup is interviewing no fewer than 1,000 U.S. adults nationwide each day during 2008. The results reported here are based on combined data from Feb. 28-March 1, 2008, including interviews with 968 Republican and Republican-leaning voters, and 1,242 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.