Ed Miliband's suggestion that trade unions should be required  to ask their members whether they wish to donate to Labour hasn't gone down well with those who lead them. After Unite's Len McCluskey pre-emptively rejected the reform in an article  for the Guardian, CWU general secretary Billy Hayes denounced Miliband on the Today programme, accusing him of "dog whistle politics". He noted that the opt-in system proposed by Miliband was a "very old fashioned idea" introduced by Tory prime minister Stanley Baldwin under the 1927 Trade Disputes and Trade Unions Act , which the 1945 Labour government repealed. In his Guardian piece, McCluskey wrote that it would "require Labour to unite with the Tories to change the law, would debilitate unions' ability to speak for our members and would further undermine unions' status as voluntary, and self-governing, organisations."
The question now is how Miliband will respond. The party is briefing that it will not impose the new system through a change in the law, with the expectation being that the unions will introduce it voluntarily. But as Hayes and McCluskey's words show, it will have trouble persuading them to do so. CCHQ has gleefully responded by describing  the opt-in proposal as "dead in the water", noting that "He [Miliband] admitted that Labour wouldn't force it on the unions-but McCluskey has already said no."
Intriguingly, however, Miliband's PPS Jonathan Reynolds has just told Sky News that McCluskey is a "little bit more supportive than that quote might suggest". He had better be right. If Miliband fails to reach agreement with the unions and then recoils from changing the law with the Tories, his epitaph will be "weak".