Gain in territory by military conquest.
From the 1940s the USA denied the claim of the USSR that the Baltic republics had joined the USSR. The UK and France ignored the annexation of Austria by Germany in 1938 although this was specifically prohibited by agreements following World War I. China annexed Tibet in the 1950s. It was the action of Iraq in endeavouring to annex Kuwait that led to the Gulf War. With the collapse of Yugoslavia, Serbia has acted to extend its territory by the incorporation of Bosnia--Herzegovina.