Ed Balls's speech isn't until this afternoon (we'll be live blogging his speech from 12pm) but it's been leading the news all morning. And with good reason. The shadow chancellor is preparing to unveil a new strategy  which will see him maintain the case for short-term stimulus but commit to long-term fiscal discipline. Balls will promise to meet the two pledges set out by George Osborne - to eliminate the structural deficit and to ensure a falling debt-to-GDP ratio - and will announce that these will be monitored by the Office for Budget Responsibility (this morning, for the first time, he said that setting up the OBR was "the right thing to do".) In addition, he will promise that any windfall from the sale of state-owned bank shares (estimated by the OBR  at £3.4bn) will be used exclusively to pay down the deficit and not to cut taxes.
Balls's smart calculation is that these promises will provide him with the political cover necessary to make the case for renewed stimulus in the form of a temporary cut in VAT  and other measures (he has promised to set out a five-point plan for restoring growth in his speech). As Keynes put it: "The boom, not the slump, is the right time for austerity at the Treasury." This is an economic truth that entirely eludes George Osborne. The eurozone crisis has demonstrated precisely why austerity is self-defeating. As Balls argued this morning, there is no reason to believe that the markets would panic if Britain slowed the pace of its deficit reduction programme, not least while the UK can borrow at near historic lows. "The markets know that if economies aren't growing, then you get into a vicious circle and your debt dynamics can actually make a debt unsustainable," he said.
Osborne will reply that Balls's answer to a debt crisis is always more debt. But his own strategy has reduced growth, increased unemployment and, consequently, slowed the pace of deficit reduction (Osborne has already been forced to announce an extra £46bn of borrowing). As the self-defeating nature of Osborne's approach becomes clearer, voters will look for an alternative. Balls is providing it.