Annexationism is the desire to be annexed by another polity.
This may represent itself on the smallest scale in small communities that desire to be annexed by a larger city.
At the largest level, entire countries may desire to become part of a neighbour.
Annexationism is related to irredentism which is the desire of larger states to annex all or part of smaller states. The opposite of annexationism is separatism.
Republic of Texas applied to join the United States.
After World War I many Austrians wanted an Anschluss, or union with Germany.
Communists with many of the early Soviet republics wanted to be annexed by Soviet Russia. This led to the Union Treaty of 1922.
Post-soviet breakaway republics of South Ossetia, Abkhazia and Transnistria want to join Russia. The degree of supposed integration varies: South Ossetia wants to unite with Russian republic of North Ossetia-Alania, Transnistria wishes to become separate federal subject of Russia and Abkhazia wishes to get associated status.
In Canada, several annexationist movements have sprung up arguing that all or some of Canada's provinces should join the United States. The most prominent were the group of influential business and political leaders, including Louis-Joseph Papineau, who signed the Montreal Annexation Manifesto of 1849; and leaders of the 1837 Rebellions in Upper (see "Republic of Canada") and Lower Canada. See under Annexationist movements of Canada.