What is a state actor

The main actor in IR are world's government.

Whilst the International stage is crowded with actors large and small that are intimately interwoven with the decisions of governments.  Such as terrorist groups, multinational corporations and others, the most important actors in IR are states.

A state is a territorial entity controlled by a government and inhabited by a population.  State government answers to no higher authority; it exercises sovereignty over its territory - to make and enforce laws

The population inhabiting a state forms a civil society to the extent that it has developed institutions to participate in political or social life. All or part of the population that shares a group identity may consider itself a nation 

The state actor includes the individual leader as well as bureaucratic organisation such as foreign ministries that act in the name of the state. 

Conflict usually arises due to the mismatch between perceived nations and actual state borders. When people identify with a nationality that their state government does not represent, they may fight to form their own state and thus gain sovereignty over their territory and affairs. 

NON STATE ACTORS

National governments may be the most important actors in IR, but they are strongly influenced by a variety of non-state actors. These actors are also called transnational actors when they operate across international border 



Can be an IGO or NGO

First, states often take actions through, within, or in the context of intergovernmental organisations (IGOs)—organisations whose members are national governments. IGOs do a variety of functions such as NATO

Another type of transnational actor, nongovernmental organisations (NGOs), are private organisation, some of considerable size and resources 

There are also Multinational companies

MNCs  provide poor states with much-needed foreign investment and tax revenues. MNCs in turn depend on states to provide protection, well-regulated markets, and a stable political environment. 

Some non state actors are substate actors: they exist within one country but either influence that country’s foreign policy or operate internationally, or both. For instance, the state of Ohio is entirely a U.S. entity but operates an International Trade Division to promote exports and foreign investment, with offices in Belgium, Japan, China, Canada, Israel, India, Australia, and Mexico- Detracting from the argument that states run international affairs solely