If liberals accept the existence of government, it is because they acknowledge that there are actions that individuals alone cannot or may not be able to carry out successfully or as successfully as government. Among those things are security (national defence, for instance), the administration of justice, the construction of countrywide infrastructures, etc. These are, according to Adam Smith, the key mission of state. But apart from doing what individuals cannot do successfully, the role of government is to set the rules of the "game" between individuals. These include ensuring that all start with equal opportunities – and then to stay aloof without interfering, the equivalent to playing the role of a referee in a football match.