Complex sentence: Relations between the United States of America and the Republic of Angola (formerly the People's Democratic Republic of Angola) have warmed since Angola's ideological renouciation of Marxism before the 1992 elections.
Split into simpler sentences: Relations between the United States of America and the Republic of Angola (formerly the People's Democratic Republic of Angola) are the relationship between the two nations. These relations have warmed since Angola's ideological renouciation of Marxism before the 1992 elections.