Barack Obama has a substantial 50 percent to 38 percent lead over Hillary Clinton among voters who say they participate in Democratic primaries, according to a Diageo/Hotline poll conducted March 28-31. The margin of error is 5.3 percent. This is a pretty different result than yesterday’s New York Times/CBS News poll which put Obama over Clinton by 46 percent to 43 percent, within the poll’s 4 percent margin of error. Gallup’s daily tracking poll conducted March 30 – April 3 has Obama ahead 49 percent to 44 percent, an uptick of two points since yesterday. The margin of error is 3 percent.

Diageo/Hotline asked Democrats how much they felt the candidates had attacked each other unfairly. Clinton was blamed for unfair attacks by a 49 percent to 42 percent margin, while only 22 percent felt Obama had launch unfair attacks versus 70 percent who said he hasn’t. Obama’s favorability rating stands at 77 percent among those who identify themselves as Democrats, a 7 point gain since February, while Clinton’s favorability rating dropped 11 points to 43 percent.

In general election match-ups, McCain leads Clinton 50 percent to 41 percent and Obama by 46 percent to 44 percent. The margin of error here is 3.5 percent. That’s not much change since February in the Clinton-McCain match-up, but it represents a reversal for Obama who had led McCain in February. The Times/CBS News poll had both Democrats ahead of McCain.