the truth is they exist by popular consent. this is no more mysterious than people believing economic fallacies, like the broken window etc. if you can make people believe that you can make them believe government is necessary. and they can and do. its up to us to teach them that broken windows are bad, and so are governments. when they learn their lesson, there will be no more consent for government as for keynesian public spending pump priming fallacies and we can all get on with our lives.