Internationalism is a movement which advocates a greater economic and political cooperation among nations for the theoretical benefit of all.  Partisans of this movement, such as supporters of the World Federalist Movement, claim that nations should cooperate because their long-term mutual interests are of greater value than their individual short term needs. Internationalism is another reaction of the same general kind - and to the very same general circumstances. Like 'nationalism', it is far more ambiguous and complicated than the self-image in which it lives. Capitalist internationality generated both nationalism and internationalism. Since the rise and fall of Napoleon's French Revolutionary Empire nationalism and internationalism have existed in permanent, uneasy tension with one another.
Internationalism is by nature opposed to ultranationalism, jingoism and national chauvinism. Internationalism teaches that the people of all nations have more in common than they do differences, and thus that nations should treat each other as equals. The term internationalism is often wrongly used as a synonym for cosmopolitanism. 'Cosmopolitanist' is also sometimes used as a term of abuse for internationalists.
In nineteenth century Britain there was a liberal internationalist strand of political thought epitomized by Richard Cobden and John Bright. Cobden and Bright were against the protectionist Corn Laws and in a speech at Covent Garden on September 28, 1843 Cobden outlined his utopian brand of internationalism:
Free Trade! What is it? Why, breaking down the barriers that separate nations; those barriers behind which nestle the feelings of pride, revenge, hatred and jealously, which every now and then burst their bounds and deluge whole countries with blood... 
Cobden believed that Free Trade would pacify the world by interdependence, an idea also expressed by Adam Smith in his The Wealth of Nations and common to many liberals of the time. A belief in the idea of the moral law and an inherent goodness in human nature also inspired their faith in internationalism.
The first international organisation in the world was the Inter-Parliamentary Union, established in 1889 by Frédéric Passy from France and William Randal Cremer from the United Kingdom. It was envisioned as a permanent forum for political multilateral negotiations. The League of Nations was formed after World War One in an attempt to solve the world's security problems through international arbitration and dialogue.
J. A. Hobson, a Gladstonian liberal who became a socialist after the Great War, anticipated in his book Imperialism (1902) the growth of international courts and congresses which would hopefully settle international disputes between nations in a peaceful way. Sir Norman Angell in his work The Great Illusion (1910) claimed that the world was united by trade, finance, industry and communications and that therefore nationalism was an anachronism and that war would not profit anyone involved but would only result in destruction.
...the voluntary federation of the free civilised nations which will eventually exorcise the spectre of competitive armaments and give lasting peace to mankind. (J.R.M. Butler, Lord Lothian 1882-1940 (Macmillan, 1960), p. 56.)
Internationalism expressed itself in Britain through the endorsement of the League of Nations by such people as Gilbert Murray. The Liberal Party and especially the Labour Party had prominent internationalist members, like the Labour Prime Minister Ramsay Macdonald who believed that 'our true nationality is mankind' (Lord Vansittart, The Mist Procession, p. 373).
Internationalism is most commonly expressed as an appreciation for the diverse cultures in the world, and a desire for world peace. People who express this view believe in not only being a citizen of their respective countries, but of being a citizen of the world. Internationalists feel obliged to assist the world through leadership and charity.
Internationalists also advocate the presence of an international organization, such as the United Nations, and often support a stronger form of a world government.
Contributors to the current version of internationalism include Albert Einstein, who believed in a world government, and classified the follies of nationalism as "an infantile sickness". Conversely, other internationalists such as Christian Lange  and Rebecca West  saw little conflict between holding nationalist and internationalist positions.
International organizations and internationalism
For both intergovernmental organizations and international non-governmental organizations to emerge, nations and peoples had to be strongly aware that they shared certain interests and objectives across national boundaries and they could best solve their many problems by pooling their resources and effecting transnational cooperation, rather than through individual countries' unilateral efforts. Such a view, such global consciousness, may be termed internationalism, the idea that nations and peoples should cooperate instead of preoccupying themselves with their respective national interests or pursuing uncoordinated approaches to promote them.
Sovereign nations vs. supernational powers balance
Internationalism, in the strict meaning of the word, is still based on the existence of sovereign nations. Its aims are to encourage multilateralism (world leadership not held by any single country) and create some formal and informal interdependence between countries, with some limited supranational powers given to international organisations controlled by those nations via intergovernmental treaties and institutions.
The ideal of many internationalists, among them world citizens, is to go a step further towards democratic globalization by creating a world government. However, this idea is opposed and/or thwarted by other internationalists, who believe any World Government body would be inherently too powerful to be trusted, or because they dislike the path taken by supranational entities such as the United Nations or the European Union and fear that a world government inclined towards fascism would emerge from the former. These internationalists are more likely to support a loose world federation in which most power resides with the national governments.
- In a less restricted sense, internationalism is a word describing the impetus and motivation for the creation of any international organizations. The earliest such example of broad internationalism would be the drive to replace feudal systems of measurement with the metric system, long before the creation of international organizations like the World Court, the League of Nations, and the United Nations.
- In linguistics, an "internationalism" is a loanword that, originating in one language, has been borrowed by most other languages. Other examples of such borrowings include "OK", "microscope", and "tokamak".
- Global Citizens Movement
- Global justice
- Global village
- International community
- World community
- "Yank" Levy
- "Internationalism is... described as the theory and practice of transnational or global cooperation. As a political ideal, it is based on the belief that nationalism should be transcended because the ties that bind people of different nations are stronger than those that separate them." N. D. Arora, Political Science, McGraw-Hill Education. ISBN 0-07-107478-3, (p.2).
- Tom Nairn (1997). Faces of Nationalism: Janus Revisited. Verso. p. 28. ISBN 978-1-85984-194-5. Retrieved 23 August 2013.
- Hans Morgenthau, Politics Among Nations, Fifth Edition, 1980, chapter on Internationalism and International Law.
- Albert Einstein, The World as I see it, 1934
- "“Internationalism . . . recognizes, by its very name, that nations do exist. It simply limits their scope more than one-sided nationalism does." Lange quoted in Jay Nordlinger, Peace They Say: A History of the Nobel Peace Prize, the Most Famous and Controversial Prize in the World. Encounter Books, 2013. ISBN 1-59403-599-7 (p. 111).
- "The European tradition...from the very beginning has recognised the nationalism and internationalism are not irreconcible opposities but counterbalances that can keep the nations in equilibrium". Rebecca West, “The Necessity and Grandeur of the International Ideal", 1935. Reprinted in Patrick Deane, History In Our Hands : a critical anthology of writings on literature, culture, and politics from the 1930s. London ; Leicester University Press, 1998. ISBN 978-0-7185-0143-3, (p. 76).
- Iriye, Akira (2002). Global Community. London: University of California Press. pp. 9, 10.
- Geyer, Martin (2001). The Mechanics of Internationalism. London: Oxford University Press.
- Ankerl, Guy (2000). Global communication without universal civilization. INU societal research. Vol.1: Coexisting contemporary civilizations : Arabo-Muslim, Bharati, Chinese, and Western. Geneva: INU Press. ISBN 2-88155-004-5.