Joe Hockey's attack on bank margins last week shows that the big four banks are now more politically isolated than at any time in the industry's history. The moment when they change their strategy may be drawing closer.Public dislike of the banks has been obvious for years. It has only grown through the global financial crisis. That's in part because of a sense that the banks were "bailed out", and in part because the crisis removed much of the big four's market competition in high-profile markets like home lending. A memorable television campaign from ANZ featuring "Barbara from BankWorld" has no doubt helped cement all the negative perceptions.Over the past three years, the banks' strategy for dealing with their public image problems has been mostly to ignore them. The bank management team that greenlighted "Barbara from BankWorld" , for instance, clearly thought the industry was safe from any meaningful community backlash. The sole major bank to adjust its strategy has been the NAB, which has decided on a low-price, low-fee "consumer champion" retail strategy.But the industry's image problems aren't going away. They're growing. The past week's events confirm that the big banks are, essentially, without political friends in Australia.Most notably, this past week the banks found the Liberal Party emphatically against them, a situation they have never before faced. On Thursday Joe Hockey, the shadow treasurer, declared that the Coalition would use its numbers in Parliament to take action against rising bank margins if the government did not. By Friday Hockey was calling for "for a social compact between the banks, the community and the government that focuses on delivering affordable credit to Australians and does not disadvantage unfairly people who are borrowing money to buy their home".  Hockey's comments were poorly-prepared, vague and took his colleagues by surprise.  Bu this populist instincts are among the strongest in the Liberal Party - the main reason he nearly became Liberal leader late last year. Hockey's criticisms dominated television through Thursday and into the weekend. Also last week:* Opposition Leader Tony Abbott signalled that he supported Hockey, saying an ineffectual government was being "stood over" by the major banks.  * At the ACCC, Graham Samuel warned once more (as he had a week earlier) that the banks' talk of the need for further rate rises  might be "price signalling", and suggested the ACCC might need expanded powers to deal with the issue. * Senior Treasury official Jim Murphy disclosed Treasury also did not believe the banks needed to push up rates by further than any RBA rate rise.* The Reserve Bank continued to deny the banks face higher funding costs, at least over recent months.The closest the banks  now have to an influential ally is the Labor government's Treasurer, Wayne Swan. Swan, though, is not exactly supportive; he see no case for the banks to raise their mortgage rates by more than the Reserve Bank raises the cash rates. And Hockey's comments make it far less likely that any action from Swan