Guaranteeing an in/out vote would have shifted the debate back onto Tory territory and could have wrecked a future Miliband premiership.
Miliband's northern fortresses are safe but Farage's party could prevent Labour winning southern and eastern marginals off the Tories in 2015.
The union is prepared to reduce the shortfall but will expect policy concessions in return.
Being beaten after just one term by a man deemed unelectable would open up space for those who understand the need to reinvent the party.
The Labour leader pressed Cameron on trade sanctions after a No. 10 document appeared to rule them out.
The Scottish First Minister's claim that independence is needed to make Scotland and the rest of the UK more "progressive" is undermined by the prospect of the election of Labour in 2015.
The Labour leader’s changes have left his party best placed to overcome the crisis of political participation.
With the former SDP leader, Tony Blair and Len McCluskey all backing his reforms, Miliband has built an impressively large coalition of support.
After today's comfortable victory, far greater political and financial challenges lie ahead for the party.
The Labour leader's message: the reforms will get working people back into politics, transfer power from MPs to party members, and help turn Labour into a movement again.