If the allegation that the union signed up members to Labour without their knowledge or consent is proven, it could be charged with fraud.
The Labour leader must use this moment to emancipate himself from the machine that won him the job in the first place.
Shadow minister Ian Austin's dramatic call for an in/out referendum next year shows how party unity is fraying.
The Unite general secretary hits back after Labour announces the end of the "union join" scheme and suspends Unite candidate Karie Murphy from the party.
The chatter in the party has been that Watson runs around the country making sure 'his' people get chosen as candidates.
Douglas Alexander, who ran the 2010 campaign, is the frontrunner.
Read the full text of the Labour MP's resignation letter to Ed Miliband.
An interview with the Yale political scientist behind Ed Miliband's big idea.
Privileges and patronage are wired into the party's institutions. Falkirk is merely the latest example.
While the Labour leader takes time to ponder the future, his party is drifting into a style of politics that looks in urgent need of consignment to the past.