Read the full CBS News poll

This poll went back to the same group of voters it interviewed in November and found Obama leading Clinton 35 percent to 28 percent with John Edwards getting 19 percent. In the November poll, Clinton led Obama 39 percent to 19 percent with Edwards getting just 9 percent. The survey said that Obama’s win in Iowa put to rest voter concerns about his electability. In the earlier poll, 72 percent gave Clinton the best chance of winning but 41 percent of those same voters now say so, while Obama went from 11 percent to 42 percent.