In the classical age of conquest moral justification for territorial expansion at the direct expense of another established polity (who often faced displacement, subjugation, slavery, rape and execution) was often as unapologetic as "because we can" treading on the philosophical grounds of might makes right.
As political conceptions of the nation state evolved, especially in reference to the inherent rights of the governed, more complex justifications arose. State-collapse anarchy, reunification or pan-nationalism are sometimes used to justify and legitimize expansionism when the explicit goal is to reconquer territories that have been lost or to take over ancestral lands.
Lacking a viable historical claim of this nature, would-be expansionists may instead promote ideologies of promised lands (such as manifest destiny or a religious destiny in the form of a Promised Land), perhaps tinged with a self-interested pragmatism that targeted lands will eventually belong to the potential invader anyway.
The Soviet economist Nikolai Kondratiev theorized that capitalism advances in 50-year expansion/stagnation cycles, driven by technological innovation. The UK, Germany, the US, Japan and now China have been at the forefront of successive waves.
This section needs expansion with: more historical examples. You can help by adding to it. (November 2017)
The militarist and nationalistic reign of Czar Nicholas I (1825-1855) led to wars of conquest against Persia (1826-1828) and Turkey (1828-1829). Various rebel tribes in the Caucasus region were crushed. A Polish revolt in 1830 was ruthlessly crushed. Russian troops in 1848 crossed into Austria-Hungary to put down the Hungarian Revolt. Russification policies were implemented to weaken minority ethnic groups. Nicholas also built the Kremlin Palace and a new cathedral in Saint Petersburg, and Pan-Slavist ambition led to further war with Turkey (the sick man of Europe) in 1853 provoked Britain and France into invading Crimea, and Nicholas died supposedly of grief at his defeat.
The German Second Reich (1871-1918) underwent an industrial revolution under Otto von Bismarck, who also reformed and expanded the army. Poles and Catholics were persecuted. Colonies were acquired in Africa and China. In 1890, Kaiser Wilhelm II dismissed Bismarck and resolved to build a world-class Navy, which led to an arms race with Britain and thence to World War I.
From 1933, the Third Reich under Hitler laid claim to the Rhineland, the Sudetenland, unification (Anschluss) with Austria in 1938 and the ocuupation whole of the Czech lands the following year. After war broke out, Hitler and Stalin divided Poland between Germany and the Soviet Union. In a Drang nach Osten aimed at achieving Lebensraum for the German people, Germany invaded the Soviet Union in 1941.
Colonialism is a form of expansionism in which the policy of a nation seeks to extend or retain its authority over other people or territories, generally with the aim of developing or exploiting them to the benefit of the colonizing country. The European colonial period, from the 15th century to the mid-20th century, had several European powers establish colonies in the Americas, Africa, and Asia.
Expansionist nationalism is an aggressive and radical form of nationalism that incorporates autonomous patriotic sentiments with a belief in expansionism. The term was coined during the late 19th century as European powers indulged in the Scramble for Africa in the name of national glory, but it has been most associated with militarist governments during the 20th century including Fascist Italy, Nazi Germany, the Japanese Empire, and the Balkans countries of Albania (Greater Albania), Bulgaria (Greater Bulgaria), Croatia (Greater Croatia), Hungary (Greater Hungary), Romania (Greater Romania) and Serbia (Greater Serbia).
In American politics after the War of 1812, Manifest Destiny was the ideological movement during America's expansionWest. The movement incorporated expansionist nationalism with continentalism, with the Mexican War in 1846-1848 being attributed to it. Despite championing American settlers and traders as the people whom the government's military would be aiding, the Bent, St. Vrain and Company stated to be the most influential Indian trading company prior to the Mexican War, underwent a decline because of the and of traffic from American settlers by Beyreis. The company also lost the partner Charles Bent on January 19, 1847 to a riot caused by the Mexican War. Many in the Cheyennes, Comanches, Kiowas, and Pawnees tribes died from smallpox in 1839-1840, measles and whooping cough in 1845, and cholera in 1849, which had been brought by American settlers. The buffalo herds, sparse grasses, and rare waters were also depleted following the war as increased traffic by settlers moving to California during the Gold Rush.
Israel was established on reacquired lands under international law and a manifest of original ownership on May 14, 1948, after the end of World War II and the Holocaust. Its government has occupied the West Bank, the Golan Heights, and the Sinai Peninsula during the Six-Day War.
Russia has had an aggressive posture since 2008, especially since 2014. Events associated with Russia are the 2008 Russo-Georgian War and Russia's occupation of South Ossetia and Abkhazia; the Russian military intervention in Ukraine, which began in 2014 with the Annexation of Crimea and the War in Donbass; and the military intervention in Syria.
The territorial evolution of the United States includes westward expansion, growing from the original Thirteen Colonies on the Atlantic coast to a country spanning the entire width of North America to the Pacific Ocean. It accomplished this by war and agreements with Britain, American Indian Wars, Native American treaties, ethnic cleansing, invasion of Spanish Florida, annexation of the breakaway country of Texas, war with and purchase from Mexico, and purchases from France and Spain. The 1856 Guano Islands Act triggered the acquisition of several islands, some of which are disputed with other countries. Some were ceded to other countries, but many remain US territories. The federal government purchased Alaska from Russia in 1867. The overthrow of the Hawaiian Kingdom was accomplished in 1893 with the participation of US citizens and military forces and allowed the annexation of Hawaii in 1898. The 1898 Spanish-American War and Philippine-American War resulted in the acquisition of Cuba, Puerto Rico, Guam, and the Philippine Islands, but Cuba was granted independence in 1902 and the Philippines in 1946. The US took control of American Samoa after the Second Samoan Civil War ended in 1899. The United States Virgin Islands were purchased from Denmark in 1917 to solve economic and security problems created by World War I. Victory over Japan in World War II resulted in the US administration of the Trust Territory of the Pacific Islands. Three Trust jurisdictions became independent countries in 1986 and 1994, each with a Compact of Free Association with the United States, but the Northern Mariana Islands became a federal territory of the United States.
The US has made no territorial claims in Antarctica but reserves the right to do so. It participates in the Antarctic Treaty and operates research bases on international territory there. The Outer Space Treaty prohibits claiming territory on other solar system bodies, but the United States sent Apollo astronauts to the Moon and planted US flags there.
The United States has been accused of neocolonialism with modern American imperialism taking the form of military and economic hegemony over the affairs of many countries and advancing American interests without annexation but with varying levels of coercion. For example, the US forced the opening of Japan in the 1850s. In the late 1800s and much of the 1900s, US corporations exercised outsized influence over several Central American countries, which became known as banana republics. They were occasionally aided by the US military, especially during the Banana Wars, from 1898 to 1934. The United States has invaded and occupied many other countries to advance its economic and security interests but has eventually returned those countries to sovereign domestic control. (For a complete list, see Territories of the United States § Former territories and administered areas.)
The US retains military bases in some of the sovereign countries that it once occupied on a notionally-voluntary basis, including in Germany, Italy, Japan, Greenland, Iceland, Iraq, and Afghanistan. Guantanamo Bay Naval Base is retained despite the protests of the Cuban government, and the US has military bases in various other countries with which it has allied.
By voluntary agreement with Panama, the United States controlled the Panama Canal Zone from 1903 to 1979. The U.S. constructed the Panama Canal and operated it until 1999, when it was turned over to Panama. The Corn Islands were leased from Nicaragua from 1914 to 1971.
In the 19th century, theories of racial unity evolved such as Pan-Germanism, Pan-Slavism, and Pan-Turkism and the related Turanism. In each case, the dominant nation (respectively, Prussia; the Russian Empire; and the Ottoman Empire, especially under Enver Pasha) used those theories to legitimise their expansionist policies.
George Orwell's satirical novel Animal Farm is a fictional depiction, based on Stalin's Soviet Union, of a new elite seizing power, establishing new rules and hierarchies, and expanding economically while they compromise their ideals.
At this point, however, we must define 'expansionism' a little more precisely. I am interpreting it to mean a desire to annex additional territory either[...]
- for the sake of more lebensraum (living space) or resources (oil, copper, timber, etc.);
- for the sake of demonstrating the national power so as to intimidate neighbours;
- because of an ideology of national greatness, power