Newly declassified documents reveal the United States supported Indonesia's takeover of Papua despite knowing Papuans overwhelmingly opposed the move.
The documents, from the US National Security Archive, show that Henry Kissenger, the former national security advisor, told President Nixon to support Indonesia's claim to Papua when Nixon visited the country in 1969.
The visit coincided with an Indonesian-run vote in the province, where bishops hand-picked by Jakarta unanimously voted to be incorporated into the republic.
Observers later said the vote was a sham.
Other documents reveal US diplomats realized the widespread local opposition to integration.
Human rights groups say at least 100,000 people have died opposing the takeover since 1969.