One immediate question posed by Tom Watson's resignation is that of who will run Labour's general election campaign. The frontrunner to fill the vacancy - Watson had been the party's campaign co-ordinator since October 2011 - is Douglas Alexander.
Alexander, currently shadow foreign secretary, ran the 2010 campaign and is admired by MPs for his intellect and strategic nous. As a figure from the "Blairite" wing of the party, who ran David Miliband's leadership campaign, his appointment would also reassure those concerned that party has drifted too far to the left since 2010.
Finally, it would offer Miliband a chance to demonstrate that it's not Len McCluskey who calls the shots. When I recently interviewed  the Unite general secretary, Alexander was one of the shadow cabinet ministers he suggested should be ignored or sacked. McCluskey told me: Ed Miliband must spend most of his waking hours grappling with what lies before him. If he is brave enough to go for something radical, he’ll be the next prime minister. If he gets seduced by the Jim Murphys and the Douglas Alexanders, then the truth is that he’ll be defeated and he’ll be cast into the dustbin of history."
The other names circulating in Westminster are Sadiq Khan (who ran Miliband's leadership campaign), Harriet Harman and Michael Dugher, who has acted as Watson's effective deputy since he was appointed vice-chair in November 2012. He previously served as Gordon Brown’s spokesman and as PPS to Miliband, and is seen as one of the most impressive of the 2010 intake.