Henry Kissinger, who died on Thursday aged 100, played a central role in the diplomatic crisis that almost led to the United States ending its alliance with Australia.

On the morning of December 20, 1972, Kissinger was in the White House and received a letter addressed to president Richard Nixon from the new Australian Labor prime minister, Gough Whitlam. It had been delivered simultaneously by two Australian diplomats – one to the side entrance of the White House, the other to the State Department.