Barack Obama had a good weekend, beating Hillary Clinton in Louisiana, Nebraska, Washington, Maine, and the US Virgin Islands. He also found time to defeat a Clinton (though Bill, rather than Hillary) in the race for the 'Best Spoken Word' Grammy, for the audiobook of his bestselling memoir 'The Audacity of Hope'.

Although Louisiana, Nebraska and Washington were expected to fall into his camp, Maine is a North-Eastern and mainly white state which Clinton had hoped to win. She lost across the state. With five contests left in February, there is the very real possibility that Clinton may not win any of the post-Super Tuesday February states.

How significant is this?

Hillary is not likely to drop out any time soon. She replaced her campaign manager yesterday, and did not do so to oversee her withdrawal from the race. She has delegate heavy states which favour her demographically coming up early in March (Ohio and Texas). If she can win both of those she will probably be considered the front runner again. But, if, as looks increasingly likely, Obama wins all the states before March 5th, the media narrative could increasingly set those Ohio and Texas up as a Clinton firewall - if she were to lose them both (which at this stage still looks unlikely), she would face strong pressure to withdraw from the race.

The key for Obama will be to try and generate the momentum from his recent and upcoming victories to give himself a chance on March 5th. But it may also require a shift in his tactics and political positioning. An interesting article in today's Guardian notes the change in Obama's rhetoric on Saturday night. This suggests that he is already looking ahead to the March states and the need to peel away some of Clinton's voting blocs - low income White and latino voters, Catholics, and Women. As the article notes, whether or not he succeeds could well determine the outcome of the race.