Tony Abbott was clearly deflecting this week when he declared his job “is not to win a popularity contest”. It’s the kind of thing no democratic politician really believes, but which you must say in the face of catastrophic polling of the order presently dogging his government. For now the popular focus is on whether or not Abbott can recover; whether this will be the fortnight that ultimately relegates him to a single term. But in truth there are bigger questions here, and the Coalition faces a conundrum far tougher than merely figuring out how to win the next election. And it’s a conundrum created well before last Tuesday.

The reason the government broke so many promises in this budget is simple: the promises they made from Opposition were wildly contradictory. You cannot rein in deficits and abolish two major taxes, and replace one of them with a climate change policy that costs billions and promise no tax hikes and quarantine education, health, defence, public broadcasting and pensions from cuts. That’s like a weight-loss diet that does away with protein but promises no cuts to cake and lard! A platform like that was always going to have its day of reckoning.

The tragedy is that Abbott didn’t need to do it. He is the Prime Minister today because Labor had descended into an unelectable mess. Even Labor’s popular initiatives such as their Gonski education reforms and the National Disability Insurance Scheme never truly threatened his dominance. Abbott had the freedom not to promise a set of contradictions. He had the freedom to keep his options open and perhaps even to tell us some budgetary truth. But he didn’t. He told us budgetary fantasy as though he hadn’t given a moment’s thought to what would happen after the election.

The result is that he brought the Coalition to government with a mandate for almost nothing. Repealing the carbon and mining taxes, sure. Stopping the boats by whatever militant means he could conceive, yes. Paid parental leave, arguably. But what else? Nothing on education, nothing on middle class welfare and especially nothing on industrial relations. In short, nothing that might help repair a budget in “crisis”, real or imagined.

But with this budget, the government was behaving as though it had the most monstrous of mandates. It was positively radical in its ambition to break the social democratic model of our welfare state. Encouraging poor people not to go to the doctor by making them pay more for it or leaving young unemployed people without any support for up to six months at a time are things you can only credibly do once you’ve sold a vision to the public. Otherwise they look like randomised cruelty. The reason the government’s reckoning has been so brutal is not merely that the public clearly thinks the budget zeroes in mercilessly on the most vulnerable. It is that it seemed to come from nowhere, without the government even bothering to convince us of the virtues of this approach first.