Until now, the argument about social security in this country has been a moral debate – and, those of us on the left have to be honest about this, it is a debate that the right has been winning.Despite frightening reportage about penury, and irrespective of whatever the poverty statistic might say, when welfare has been talked about down the Dog and Duck, it has chiefly been in terms of the 9am cans of lager, the layabouts and "jobs on the side" highlighted on Channel 4's Benefit Street. As a man who projects great personal zeal, Iain Duncan Smith prospered politically by embodying this moralizing mood. Finally, however, the welfare debate is beginning to switch from a discourse of ethics, to a more run-of-the-mill question of government incompetence. Some of us warned a long time ago that the universal credit was no panacea, but a mere rationalization which promised real but modest theoretical advantages in return for serious practical risks. We warned, too, that officials made a "nervous sucking sound" when asked about just how easy it was going to be to move clients from a whole host of different benefits on to a single system. But the rhetoric of simplifying things by replacing six benefits with one was irresistible for pundits who know little about social security, beyond a vague (and justified) sense that it creaks with complexity. Unfortunately, the complexity reflects the messiness of the real world, which is exactly where it is now running aground. To recap, last month Duncan Smith used the cover of George Osborne's autumn statement to bury bad news about the universal credit timetable for delivery slipping. Then this week, my colleague Shiv Malik reported that Francis Maude's crack team of IT experts were stepping back from the reform not, according to official minutes, because the technical problems were fixed nor because these taxpayer-funded officials were needed to go and serve the public interest elsewhere, but simply because the Cabinet Office felt it was time for the Department for Work and Pensions to "take ownership" of its own shambles. Now, the Guardian reveals one of the harshest of all the £25bn in benefit cuts thus far announced – the bedroom tax – has been applied with complete incompetence. By failing to rewrite old regulation before driving through the new legislation, the Department for Work and Pensions has failed to create the legal license that was needed to enforce this housing benefit reduction on thousands of tenants who have been enduring it since last year. The upshot will be more administrative chaos, compensation claims and – very likely – in some cases the eviction of tenants who had legal right to remain where they were. The bedroom tax, which requires poor council tenants to pay £14-£22 for "spare rooms", is already one of the most controversial of the welfare cuts, losing popularity over the year, as it has become plain that its effects can include the uprooting of disabled people from adapted homes, and the reality that it imposes an expectation that tenants should move even when there is nowhere else for them to go. Now, however, it is emerging that the coalition is not only cutting with cruelty, but also cutting without competence. That is the sort of combination that might, just might, start to reset a debate in which the right has made all the running.