Towards the start of the second world war the allies wanted to assassinate Hitler because it seemed like it would strike an important blow against the nazis. Later on, they gave up that idea because he was making lots of mistakes and they realised that while he was doing everything wrong, it prevented someone else from coming in and doing everything right. Hiter became an asset to his foes and a liability to his allies because he was incompetent; a fact which was not lost on the nazis as they themselves attempted to assassinate him.
This unfortunate situation is no doubt one with which Ed Miliband will sympathise. Unfortunately, however, while Labour desperately needs to replace Ed, the right time to do it was 12 months ago, and it will involve a huge amount of risk in backing relative unknowns as none of the established figures are up to the job,