The government does not have to turn over secret diplomatic documents concerning the 1972 reversion of Okinawa because in all likelihood they were destroyed, the Supreme Court ruled Monday, upholding a lower court finding.

In its 2011 decision, the Tokyo High Court accepted the government's argument that the documents were disposed of before the law on freedom of information was enacted to avoid exposing Japan's secret negotiations with the United States.

The deal was made secret because the Japanese government didn't want the public to think Okinawa had been "bought back" from the United States, according to the high court ruling.