Millions of people, including the elderly and some of the most vulnerable members of society, rely on them to survive. Yet around a quarter could close their doors soon if a ministerial decision goes the wrong way.
The fate of 3,000 post office branches hangs in the balance as the government decides the future of a card account that cannot be used in banks or shops but gives vital access to pensions and other state benefits for around four million people. These customers also happen to be the people who are already suffering the most, or will be hardest hit, by the credit crunch, rising fuel prices and inflation.
There are many lessons to be learnt from the present economic crisis, not least from the fiasco that forced the government to rescue four high street banks. One of the reasons why the government had to make such a dramatic intervention is that if these banks had gone to the wall then they would have taken thousands of branches along with them.
That apocalyptic scenario would have left the post office network as the last financial bastion holding many communities together. Much has been made of the disastrous impact of post office closures on rural areas, but this is a major issue for towns and cities too. The government needs to think again about what post offices mean to their areas rather than just balance sheets.
While all eyes have been on events across the Atlantic, it is worth recalling the arguments of Thomas Kuhn, the almost-forgotten American intellectual who coined the concept of "paradigm shift". The USA sees its post offices in a very different way to our government. They are vital infrastructure, as important as transport, and are properly subsidised. A similar paradigm shift is needed in Whitehall. Post offices are part of the UK's infrastructure. Any government considering their future should look to broaden their services and appeal, not shut them down.