The Labour leader shifts the focus from the unions by calling for new limits on MPs' outside earnings and a cap on party donations.
While the rewriting of Clause IV by Blair was of largely symbolic significance, the changes proposed by Miliband would have dramatic consequences for Labour's funding.
Former PM tells Sky News "this is big stuff and it takes a real act of leadership to do it".
Labour suggests it will not impose the reform by changing the law with the Tories, but if the unions resist that may be the only option.
If the Labour leader is to be a consistent supporter of democracy and transparency, he cannot defend a system that allows unions to donate millions from their members without permission.
I joined the union as a fresh-faced student idealist but the camaraderie which I expected never materialised.
Blair was able to win more support for a full-scale invasion than Cameron can for arming a rebel group.
Tory MP Bob Neill's letter to the Metropolitan Police contains no evidence that the law may have been broken in seats other than Falkirk.
It would give greater legitimacy to Labour funding and force trade unions to make a positive case for supporting the party.