Indonesian Islamic Union Party

Islamic Association Party of Indonesia () was an Islamic political party in Indonesia. In 1973 it was merged into the United Development Party.
Origins.
The Sarekat Islam (Islamic Association) was a pre-war political organization in the then-Dutch East Indies. Following a split brought about by the increasing influence of the Indonesian Communist Party (PKI), at the organization's 1923 conference, Tjokroaminoto set up the Islamic Association Party () to rid the organization of the PKI. The PSI supported Sukarno's efforts to united Indonesian political organizations following the establishment of the Indonesian National Party (PNI) in 1927. The PSI changed its name to the Islamic Association Party of Indonesia (PSII) in 1929 and in the next few years attacked nationalism of other parties, claiming that nationalism came from men rather than God. The party's fortunes waned in 1934 when the Dutch colonial authorities clamped down on nationalist activities and party leader Tjokroaminoto died. Following this, political Islam broke into factions. In 1942 the occupying Japanese banned all political activity. However, in 1943 the Japanese established an organization called Masyumi in an attempt to control Islam in Indonesia. The following year the Masyumi military wing established, with many pre-war pro-cooperation faction PSII members in the leadership.
Post-independence.
In 1947, the PSII split from Masyumi in 1947 because of disagreements with the leadership, especially Natsir. The new PSII claimed to be same organization as pre-war party. It did not cooperate with Masyumi after the split although leaders of both parties claimed their differences were minor. It was not as strong as Masyumi nationally, but several of its members served in Indonesian cabinets in the 1950s.
The party came fifth in the 1955 legislative election with 2.9 percent of the vote, winning eight seats in the People's Representative Council. In the 1971 election it won 2.4 percent of the vote and ten seats, but shortly after was fused into the United Development Party, ending its existence as a separate political entity.
Although the party was formed again after the fall of Suharto, they received only 1 seat following the 1999 election.