Ready for another make-or-break primary day on May 6th? This time, though, it could be Barack Obama sweating out the results. The new Insider Advantage poll shows Obama losing a double-digit lead over two weeks to fall slightly behind Hillary Clinton in North Carolina, just as the Jeremiah Wright scandal peaked. If Obama cannot hold North Carolina, it will likely have superdelegates questioning whether the damage has gone too deep for recovery:

A survey of 571 registered likely voters in North Carolina’s May 6 Democratic primary shows Sen. Hillary Clinton having moved from a double digit deficit in an InsiderAdvantage poll taken in mid-April to a two point lead over Sen. Barack Obama in this telephone survey, conducted April 29. The survey was weighted for age, race, gender, and political affiliation. It has a margin of error of plus or minus 3.8%

The results were:

Hillary Clinton: 44%
Barack Obama: 42%
Undecided: 14%

Obama led the poll on April 14, 51-36. The dramatic decline in support could come from a number of sources, including a terrible debate performance on April 16 or the April 22 defeat in Pennsylvania, which may have rattled some North Carolina voters. However, the likeliest explanation is Jeremiah Wright, and that might not have finished reverberating in either NC or Indiana.

The biggest movement, according to pollster Matt Towery, comes from white voters over 45, but that’s hardly Obama’s only problem. He only commands majorities among 18-29 and 30-44 age groups, the former of which has a habit of not showing up at the voting booth. He doesn’t poll above 36% in the remaining age groups, which have heavily comprised Democratic turnout of late.

His normal support among African-American voters appears to have eroded as well. Obama only captures 64% of it in this poll of likely voters, while Hillary gets 20%. That’s a lot better than her 92-8 drubbing among black voters in Pennsylvania, and it indicates that Obama has lost ground in his base. If he loses 20% of the black vote in North Carolina, his candidacy will be seriously imperiled.

The key will be to see how Obama’s repudiation of Wright plays in the state. Will it win him some white, working-class voters whom Wright had offended with his remarks? Or was that damage already done, and will the repudiation cause a deflation in the enthusiasm generated by African-American voters?

A loss in North Carolina will give Hillary an opportunity to run the table straight through to the convention, with perhaps only Oregon lining up against her. It will also underscore her argument that Obama peaked too early and has lost momentum and support, and that superdelegates should go with the hot hand. Hillary could even make an argument that a decent showing among black voters in North Carolina could indicate that their critical bloc will not bolt the Democratic Party if Obama loses the nomination at the convention.