'Republic of the United States of Indonesia';[a] abbreviated as RIS or RUSI, also known as Federal Republic of Indonesia) was a short-lived federal state to which the Netherlands formally transferred sovereignty of the Dutch East Indies (except Netherlands New Guinea) on 27 December 1949 following the Dutch–Indonesian Round Table Conference.

However, the Dutch were able to reassert control over most of the area previously occupied by the Japanese Navy, including Borneo and the Great East.

[11] A second Dutch military action, Operation Kraai, aimed at destroying the Republic, was launched on 18 December 1948.

Despite recapturing the major cities of Java, including the republican capital of Yogyakarta, and all of Sumatra except Aceh in the far north, it triggered the protest resignation of the cabinets of the State of East Indonesia and Pasundan (West Java) and the Sultan of Yogyakarta from his position as regional head.

However, many Indonesian nationalists believed that the Dutch had insisted on a federal state in an attempt to weaken or even break up the new nation, a manifestation of a "divide and conquer" strategy.

[17][18][19] The RIS comprised sixteen main entities: seven states (negara), including the "Republic of Indonesia" consisting of parts of Java and Sumatra (a combined population of over 31 million); and the nine formerly directly-ruled territories (neo-lands, Dutch: neo-landschappen).

[17][20][21] From the outset, the majority of Indonesians were opposed to the federal system resulting from the Round Table Agreement.

Finally, there were insufficient ethnic or cultural ties between people in the individual states to overcome the dominance of Java.

[40][41][42] Even those who supported the idea of a federal state wanted the form of it to be decided by the people of Indonesia through an elected Constitutional Assembly, rather by than the former colonial power.