CANBERRA, Australia — A historian is going to court this month in an attempt to force Australian authorities to release secret letters that would reveal what Queen Elizabeth II knew of her representative’s shocking scheme to dismiss Australia’s government more than 40 years ago.

The National Archives of Australia has categorized the correspondence between the British monarch, who is also Australia’s constitutional head of state, and her Australian representative, Governor-General Sir John Kerr, as “personal” and might therefore never be made public.

The letters would disclose what, if anything, the queen knew of Kerr’s plan to dismiss Prime Minister Gough Whitlam’s government in 1975 to resolve a month-old deadlock in Parliament.

It remains the only time in Australia’s history that a democratically elected federal government has been dismissed on the British monarch’s authority. Kerr’s surprise intervention placed unprecedented strain on Australia’s democracy and bolstered calls for the nation to split from its former colonial master by becoming a republic. Suspicions of a U.S. Central Intelligence Agency conspiracy persist.

Jenny Hocking, a Monash University historian and Whitlam biographer, will argue in the Federal Court in Sydney on July 31 — the only hearing day of the case — that the letters should be released regardless of the queen’s wishes because Australians have a right to know their own history.

“To me, it’s a point of national humiliation that we have to be even considering asking the queen whether we can look at these key records in our own history,” Hocking told The Associated Press.

She started the case in October last year, is represented by lawyers free of charge and has raised more than $28,000 through crowd funding in case she loses and is ordered to pay the Archives’ legal costs. The legal argument has been presented so far in written submissions.

While Hocking is taking on the Archives alone, she has a powerful ally in Prime Minister Malcolm Turnbull, who agrees that the communication between two such key figures in Australia’s constitution should not be secret.

The Archives, Buckingham Palace and the governor-general’s official residence, Government House, have all declined AP’s requests for comment.

The court is being asked to remove the letters from their “private” and “personal” classification, so that they could become public 30 years after they were written like other government documents held in the Archives.

Under an agreement struck between Buckingham Palace and Government House months before Kerr resigned in 1978, the letters covering three tumultuous years of Australian politics will remain secret until 2027. The private secretaries of both the sovereign and the governor-general in 2027 would have the option of vetoing their release indefinitely.

The British royal family is renowned for being protective of their privacy and keeping conversations confidential.

The family went to considerable lengths to conceal letters written by the queen’s son and heir, Prince Charles, in a comparable case in Britain that was fought through the courts for five years.

Britain’s Supreme Court ruled in 2015 that 27 memos written by Charles to British government ministers could be made public despite objections that their publication might damage public perceptions of the future king’s political neutrality.

Years of dogged research by journalists and historians have pieced together answers to many of the questions surrounding how and why Whitlam’s government was dismissed and who was behind it.

Kerr, who died in 1991, rejected in his memoirs media speculation that the CIA ordered Whitlam’s dismissal over fears that his government would close the top secret U.S. intelligence facility that still exists at Pine Gap in the Australian Outback. In the 1985 Hollywood spy drama “The Falcon and the Snowman,” a CIA plot to oust Whitlam motivated a disillusioned civilian defense contractor played by Sean Penn to sell U.S. security secrets to the Soviet Union.

Australia’s governor-general, who is chosen by the prime minister and appointed by the monarch, is a largely ceremonial role. Turnbull, as a journalist in 1975, described Kerr as an “unelected ribbon cutter.”

Few realized before 1975 that the role carried unwritten constitutional powers to sack a prime minister in a crisis. Lawyers still argue about whether the so-called reserve powers even exist.

The constitutional crisis came in 1975 when the opposition tried to force Whitlam to call general elections by blocking in the Senate routine legislation that allowed the government to pay public servant salaries and deliver services.

Kerr fired Whitlam during a brief meeting at Government House, called an election and appointed opposition leader Malcolm Fraser as prime minister. Weeks later, Fraser’s coalition won a resounding election victory. But his eight-year tenure was always tainted by how it began. Whitlam branded Fraser “Kerr’s cur” and the insult stuck.

Kerr’s critics argue that he should have warned Whitlam of what he was planning and given the prime minister an option of remaining the government’s leader if he agreed to an election.

Former High Court Chief Justice Anthony Mason, who secretly assured Kerr he had the power to sack Whitlam, only revealed in media interviews in 2012 that he had also advised the governor-general that Whitlam should be warned.

Kerr explained that he chose an ambush because Whitlam might have fired him first if the governor-general had shown his hand.

Turnbull, who believes an Australian president rather than a British monarch should be Australia’s head of state, argues that Kerr should not have been worrying about saving his own job when deciding how to act as governor-general.

Weeks after becoming prime minister in 2015, Turnbull said he would ask the Palace and the current Governor-General Peter Cosgrove to release the letters. But Turnbull has remained tight-lipped on progress since then.

Philip Benwell, a leading advocate for the British monarch remaining Australia’s head of state, argues that the letters should remain private. The political system would become untenable if the queen’s opinions were known to be at odds with her government, he said.

“It would cause a constitutional crisis if the queen’s personal opinions became known,” Benwell said.