The poll found that after 40 Democratic primary elections, Obama has made substantial gains across most major demographic groups in the Democratic Party, including men and women, liberals and moderates, higher and lower income voters, and those with and without college degrees.

For the first time in a New York Times/CBS poll, he moved ahead of rival Sen. Hillary Clinton (D- NY) nationally, with 54 percent of Democratic primary voters saying they wanted to see him nominated, while 38 percent preferred Clinton.

US Democratic presidential candidate Senator Barack Obama (D-IL) campaigns at a rally in Corpus Christi, Texas February 22, 2008.(Xinhua/Reuters Photo)