at the opening of the twenty-first century, governments have become the most powerful organs of nation states. They determine the direction, if not always the detail, of domestic policy. They decide how public money should, and should not, be spent. Foreign policy is made almost entirely by governments. And control of military power is likewise the preserve of the executive. Whatever the truth of the claim that, in this era of apparent globalization, states are no longer the only or even the most powerful units of political power, within nation states governments still retain very considerable power. This is not to say that their power can never be checked. Governments may rule, but they do not always rule supreme. In democracies the personnel of the executive is subject to the verdict of the electorate; the policies of the executive may be subject to political or parliamentary accountability; and the legality of executive action may be reviewed by the courts of law.