 National security refers to the security of a nation-state, including its citizens, economy, and institutions, and is regarded as a duty of government. Originally conceived as protection against military attack, national security is now widely understood to include non-military dimensions, including economic security, energy security, environmental security, food security, cyber security, etc. Similarly, national security risks include, in addition to the actions of other nation-states, action by violent non-state actors, narcotic cartels, and multinational corporations, and also the effects of natural disasters. Governments rely on a range of measures, including political, economic, and military power, as well as diplomacy to enforce national security. They may also add to build the conditions of security regionally and internationally by reducing transnational causes of insecurity, such as climate change, economic inequality, political exclusion, and nuclear proliferation.