Matthew Norman: Will it be off with his Ed, or bye George Osborne?

How both now deal with their economic supremos will do much to decide the election

The virus known to Westminster epidemiologists as "reshuffle fever" is on the loose again. That's a very grand name, but since only the political classes lack the antibodies of ennui and disdain to ward off infection, it can hardly be called a pandemic. Every year or two it tends to deposit a few corpses in the Cabinet and Shadow Cabinet morgues while leaving the rest of us unaffected. But this time it feels different, and in two perfectly self-contradictory ways.

The paradox with any imminent changes to key front bench positions is that they couldn't matter more and have seldom mattered less. The identity of the Chancellor and his Labour shadow could not be less important in the continuing absence of the debate that dare not speak its name. One day, it will become impossible to postpone the nasty little chat about how to manage the irreversible decline in living standards, dictated by the impossibility of competing with the emerging Asian and Latin American powerhouses without a highly educated workforce. In this bleak context, fixating on who faces whom across the despatch boxes, rising to their feet to yell the similarly vacuous verities with identically misplaced certainty, feels like a criminal waste of human existence.

Then again, there is a general election to be won in a couple of years, and how David Cameron and Ed Miliband deal with their economic supremos now may do more to decide it than any other decision they take. Each leader is saddled with a lethal liability in George Osborne and Ed Balls respectively, and faces a finely balanced judgment about whether to dispose of these gruesome paradigms of impregnable arrogance,

According to the latest polls, the public wish Cameron to remove Osborne, while backbench opinion apparently favours a job swap with the Foreign Secretary. I can't imagine that even the dimmest among them believes William Hague has any solution to the systemic problems of the economy, let alone the nightmare of the eurozone. But the punters are fond of Mr Hague, or at least don't come over all Uncle Dick at the sight of him, giving him a handy electoral edge over Osborne even if he proved as cack-handed as the Treasury incumbent. The public have less strong feelings about the Shadow Chancellor, presumably because they have the good fortune to know little about Ed Balls. But we mega-nerds who have studied him for years suspect his power to cost Labour a general election more than matches Mr Osborne's ability to damage the Tories.

Tales of growing tension between Miliband and Balls – Ed M resenting Ed B's cockily domineering nature; B's overwheening personal ambition dovetailing merrily with his contempt for M's presentational failings (yeah, like he's George Clooney) – will do nothing to cause a run on the nation's smelling salts reserves. These reports merely remind us why Little Ed denied Balls the Shadow Chancellorship when he constructed his first frontbench team. Knowing the rival he had crushed in the leadership election to be serially and uncontrollably disloyal, he was not keen to grant him that lavish powerbase. It was his rotten luck that Alan Johnson's indolence and marital strife saw him scurry off so soon, at which point Miliband saw no option but to make the appointment he had wisely avoided before. This was his first and so far only serious mistake, just as Cameron's gravest error as opposition leader was not replacing the post-Corfugate Osborne with Kenneth Clarke.

So now, simultaneously for the PM and his would-be replacement, arrives a test of character that may define their careers. Does either have the nerve, guts and brutality to do what, for all the inherent danger, is clearly required? For both, action may be as fraught with fears as it is essential to their electoral chances, though for entirely different reasons. Cameron will be mortified by the thought of demoting a close personal friend and closer political partner, which does him more credit as a man than as a politician. Butchery is a vital leadership skill, and he is no Dewhurst. He may disguise his support for Osborne, even to himself, as the fruit of the Blair vs Brown lesson about what happens when the two tribes from Nos 10 and 11 go to war. But what he may interpret as statesmanlike loyalty will strike others as plain feebleness.

For his part, Mr Miliband will fret about the havoc Mr Balls – assuming he did the Kevin Keegan queeny flounce-out when offered a lowlier post – could wreak from the backbenches.The dynamic would hardly be simplified by the wounded and possibly vengeful presence of Mrs B, Yvette Cooper, at the Shadow Cabinet table. Having steered his party away from the rocks of civil warfare into which one automatically assumed it would long since have crashed, Little Ed would take a massive gamble by fiddling with the rudder now.

Of the two men, Miliband has the reputation as the taker of calculated risks. The metaphorical fraternal bonds Cameron seems incapable of shrugging off didn't constrict Little Ed so far as a genetic brother, which is why he deserved the leadership in the first place. He could cement a consistent but still slightly flaccid-feeling opinion poll lead if he removed Balls and inveigled Alistair Darling to shadow the post he held under Gordon Brown. But regardless of the replacement, it would be folly to leave Balls, for all his energy and talent, in place to hijack whatever new policy direction Jon Cruddas eventually maps out for Labour. Sometimes in politics, avoiding an apparently colossal risk is incomparably riskier than shutting the eyes, crossing the fingers and doing nothing at all.

This appears to be Cameron's management style, as he will confirm should he continue to deposit his blind faith in the mystical recuperative powers of our locked-in syndrome economy under as mistrusted and degraded a Chancellor as Osborne. Ed Miliband will always lack the PM's gloss, but an age of perpetual crisis and deepening despair is not one for the affable diffidence of the sleepy, magic circle 1950s. A few of us have been convinced for a while that, of the two candidates, Miliband is temperamentally far better equipped for these times. If he finds the courage to guillotine Ed Balls while Cameron leaves the Osborne neck untouched, he would take a giant step towards persuading the country.