PRINCETON, NJ -- Barack Obama and Hillary Clinton are roughly tied in national Democratic preferences -- 47% for Obama vs. 45% for Clinton -- according to Gallup Poll Daily tracking conducted March 6-8.

Support lines for the two Democratic contestants have now switched since Gallup's March 7 report, and Obama is back on top, although his two percentage point lead is not statistically significant.

Clinton gained on Obama in the days leading up to last week's March 4 primary voting, but her successful showing -- winning three of the four elections held that day -- failed to boost her candidacy nationally.

Obama had a solid victory in Saturday's Wyoming caucuses, winning 61% of the vote and more than half of the delegates. Any impact this might have on national Democratic preferences will not enter the three-day rolling averages in Gallup Poll Daily tracking until Monday's report. -- 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 March 6-8, 2008, including interviews with 1,282 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.

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