Liberal internationalism is a foreign policy doctrine that argues that liberal states should intervene in other sovereign states in order to pursue liberal objectives. Such intervention can include both military invasion and humanitarian aid. This view is contrasted to isolationist, realist, or non-interventionist foreign policy doctrines; these critics characterize it as liberal interventionism.
Liberal internationalism emerged during the nineteenth century, notably under the auspices of British Foreign Secretary and Prime Minister Lord Palmerston, and was developed in the second decade of the 20th century under U.S. President Woodrow Wilson. In this form it became known as Wilsonianism.
The goal of liberal internationalism is to achieve global structures within the international system that are inclined towards promoting a liberal world order. It foresees a gradual transformation of world politics from anarchy to common institutions and the rule of law. To that extent, global free trade, liberal economics and liberal political systems are all encouraged. In addition, liberal internationalists are dedicated towards encouraging democracy to emerge globally. Once realized, it will result in a 'peace dividend', as liberal states have relations that are characterized by non-violence, and that relations between democracies are characterized by the democratic peace theory.
Liberal internationalism states that, through multilateral organizations such as the United Nations, it is possible to avoid the worst excesses of "power politics" in relations between nations. In addition, liberal internationalists believe that the best way to spread democracy is to treat all states equally and cooperatively, whether they are initially democratic or not.
Examples of liberal internationalists include former British Prime Minister Tony Blair. In the US, it is often associated with the American Democratic Party; however, many neo-conservative thinkers in the United States have begun using similar arguments as liberal internationalists and, to the extent that the two ideologies have become more similar, it may show liberal internationalist thinking is spreading within the Republican Party. Others argue that neoconservatism and liberal internationalism are distinctly different foreign policy philosophies and neoconservatives may only employ rhetoric similar to a liberal internationalist but with far different goals and methods of foreign policy intervention.
Commonly cited examples of liberal interventionism in action include NATO's intervention in Bosnia and Herzegovina; their 1999 NATO bombing of Yugoslavia; British military intervention in the Sierra Leone Civil War; and the 2011 military intervention in Libya.