A loan by any other name

Ideas for nationalizing banks are all the rage. One question though: after a nationalization of banks, what would be the rationale for not nationalizing insurance companies? The balance sheet of a company like Aflac doesn't look much better than some of the banks being identified as candidates for government takeovers: thin on capital relative to all the things that could go wrong with their assets. Without a convincing rule for where to draw a line, bank takeovers would just be more of the ad hockery whose track record is already not so good.