Barack Obama has erased a once substantial deficit to climb into a virtual tie with Hillary Clinton in the Democratic presidential race, according to a Reuters/Zogby poll released on Wednesday.
Among Republicans, John McCain charged to the front of a shifting presidential field, shooting past Mike Huckabee and a fading Rudy Giuliani as the opening contests of the 2008 White House campaign dramatically reshaped the races in both parties.
Heading into potentially crucial contests in Nevada, South Carolina and Florida, the campaign to choose candidates for the November election to succeed President George W. Bush has shown deep volatility.