On her deathbed, you may recall, the American writer Gertrude Stein is alleged to have repeatedly asked her companion Alice B Toklas: "What is the answer?" Then, when the silent Toklas failed yet again to reply, Stein supposedly summoned her remaining strength to utter her famous last words: "In that case," she asked, "what is the question?"

Today, a Gertrude Stein teaser looms over British politics. What is the next big question around which political life will define itself? In its wake, almost as importantly, comes another, umbilically linked. Which party is positioning itself to supply the answer to the next big question that will seem most credible to most voters? The party that gets the answer right will be well on the way to winning the next general election.

We know what the last two big questions were. The first was: "What do we do about the bankruptcy of the banks?" Gordon Brown and Alistair Darling got part of the answer right – by decisively deploying the unique power of government to stop the collapse – but dithered too long about answering the other part, about what needed to be done with the banks in the longer term.

We also know the more recent big question. "What should be done about the budget deficit?" Darling wanted to answer it honestly but carefully. Brown didn't want to answer it at all. The Conservatives and Liberal Democrats sensed an opportunity. They stepped forward boldly to cut the deficit, not as carefully as Darling might have done, but radically and even violently.

The deficit remains the defining question of the hour. But the form of the question has changed. How, not whether, is increasingly the key word. The cuts have begun. Many more are imminent as the new financial year begins. Taxes are about to rise. Even the prospect of a second, oil-price-driven recession of the sort Chris Huhne warned about this week seems unlikely to deflect George Osborne from the course on which he has invested so much when he delivers his next budget this month. Government unpopularity, compounded by disruptive changes in schools and the NHS, is inevitable. A senior cabinet minister says baldly that the next 12 months will be "shitty".

The coalition parties did not answer the whole of the last big question perfectly. But the public mood was, and still is, that the deficit had to be addressed. The voters initially gave the coalition what Stanley Baldwin used to call a doctor's mandate. By and large, they still accept that something has to be done. Increasingly, however, they don't like the doctor's medicine. Big things like the NHS shake-up and smaller things like the forestry debacle make some people fear this doctor may occasionally have a shade of the Shipman about him.

In the months ahead, this process is likely to continue. How long the deficit will hold sway as the decisive political question is difficult to predict. Cameron and Osborne still get mileage from talking about Labour's mess. That is likely into 2012. But inexorably it is the cuts – and above all their consequences for the fabric of Britain – that will become more salient. The coalition, Conservatives in particular, will increasingly own the economic situation, not Labour.

As this happens, the last big question will fade from prominence and be replaced. The challenge for politicians is to accurately anticipate the nature of the next big question and define it in their own terms. The sudden rise in oil prices is a powerful reminder of both the fragility of the western economies and the difficulties involved in predictions. But making the right call is crucial, all the same.

One thing is certain. The next big question will not be entirely about the morality of the current cuts. All parties, Labour as much as the coalition, will be mistaken if they assume that politics in 2014-15 will still be defined by whether cuts and tax rises were needed in 2010-11. Things will have moved on, not ossified. Unless the economy goes very wrong indeed, which is possible but not probable, the big debate in 2014 is likely to be about the Britain that is emerging from the cuts, about safeguarding such gains as have been won from the period of fiscal austerity, and about mitigating some of the worst losses and wounds.

This is good and bad news for Labour. It is widely understood, even by the many Labour MPs who face almost daily exposure to constituents who have lost or are losing vital lifelines in the form of jobs, benefits and services, that Labour will stand little chance of regaining a majority by simply being the angry party, opposed to the cuts and the shake-ups in services. Fighting the cuts will not be enough. Labour has to be able to say something promising not just to the poor, but to those who think of themselves at least as much taxpayers as public sector dependents.

Equally, though, the Tories cannot expect to win in 2015 by simply repeating Harold Macmillan's 1959 slogan that "Life is better under the Conservatives, don't let Labour ruin it." Fear of Labour will certainly be central to the Tory campaign, but the 2015 election will not take place against a backdrop of 1959-style prosperity. It looks likely to take place against one of continuing economic fragility and unequal expectations. A lot of people may have been out of work for a long time in run-down cities and towns – the 1980s revisited. Benefit changes and localism may have deepened the divide, especially in housing.

For the Lib Dems the challenge is slightly different. They need to be able to say not just that the coalition has worked, but that the junior partner has a record of achievements that have made the past five years better than they would otherwise have been.

My hunch is that the next big question will have echoes of the postwar moods of the 20th century and will reflect a lot of anger with the past. "What can we do to make sure we never have to go through something like that again?" is my suggestion. It is a question that can be answered in many competing ways. Appeals to hold on to nurse for fear of something worse for some. Exhortations to do things completely differently for others. Claims that action on a particular issue – immigration, EU membership, environmental sustainability – is all that matters for others.

The next big question for Britain, in other words, may still be posed in very uncertain economic times. But it is likely to be a surprisingly ambitious question all the same. All we need now is a credible answer.