Insider Advantage has the poll, that supports another recent poll that showed Obama up by 21 in the Tar Heel State.

From Southern Political Report:

“If you are voting in the Democratic primary and the election were held today, who would you vote for?”

Barack Obama (49%)
Hillary Clinton (34%)
Undecided (17%)

The poll was conducted by InsiderAdvantage/Majority Opinion on March 26. It sampled 406 likely voters in the May 6 North Carolina Democratic presidential primary. The margin of error is plus or minus 5%. The data have been weighted for age, race, gender and party affiliation.

“Firewall state” has been the king of clichés during this campaign season, but that term has never applied more than North Carolina does for Clinton. If she loses badly here, regardless of any modest gains in the national delegate count, her candidacy may be done unless her primary victories in Florida and Michigan somehow end up being seated at the national nominating convention.

Most troubling for Clinton is that the trends in our polling of North Carolina show that a modest but significant portion of whites are drifting from Clinton back into the “undecided” column. Twenty percent of whites are undecided.“

If I were Hillary’s people, I’d start hammering North Carolina with ads, etc. She has to finish strong here if she has any hope of closing that delegate gap.

Politics Poll: Obama Up 15 In North Carolina