Sir John Kerr was spurred to dismiss former prime minister Gough Whitlam partly by the fear that Mr Whitlam would go to the Queen first and demand the governor-general's removal, his letters reveal.
Mr Whitlam had told him "sometimes jocularly, some times less so, but on all occasions with what I considered to be underlying seriousness" that "the crisis could end in a race to the palace to see who could get there first"," Sir John told the Queen's private secretary, Sir Martin Charteris.
In late October at an official dinner, Mr Whitlam had joked: "It could be a question of whether I get to the Queen first for your recall or you get in first with my dismissal," Sir John said in a letter to the palace. "We all laughed."
While Sir John said he had the power to dismiss Mr Whitlam without going to the palace in advance, he was worried that if Mr Whitlam tried to head him off by going to the Queen first, it would put her in a difficult situation.
The Palace letters show Sir John wrote to the palace every few days during the unfolding crisis of 1975, long and detailed letters in which he recounted conversations, possible scenarios and doubts about what he should do.
His letters reveal that he was canvassing the possibility of a constitutional crisis no sooner than he became governor-general in mid 1974, repeatedly discussing the likelihood that the Liberal Opposition would refuse to pass Mr Whitlam's supply bills to force an election.
In September 1974, Sir John told Sir Martin about the "malaise " at the head of the public service, where bureaucrats who had worked for 23 years under a conservative government felt that Mr Whitlam was "brushing aside" their advice, and making Labor-friendly appointments.
"We now all await the Budget and its impact upon the economy," he told Sir Martin, writing again in November about rising inflation and unemployment.
"This will inevitably raise the question, around the middle of next year, of another precipitated election which would have to be based on denial of supply by the Senate. .. The question will be whether the Leader of the Opposition feels ready to force another election somewhere about August by denying supply in late June."
Mr Fraser, he told the Queen, was of "patrician" origin and had "a reputation of being strong, intelligent, aggressive and tough minded"
In mid 1975, he wrote that Mr Fraser could bring down the government by refusing supply later in the year, precipitating an election in early December.
"However, he would be taking the country over under circumstances in which the economic problems would be awkward in the extreme and he may wish to let the present Government carry the burden of a hard budget," he wrote.
Mr Whitlam's budget soon after appeared to allay the possibility, but still, at the end of August 1975, Sir John wrote to Sir Martin that people "seem to hold the view that it is very possible indeed that economic circumstances in the early part of next year will be such as to enable, in and indeed force Mr Fraser to deny supply in April/May, and to produce a double dissolution towards the end of the first half of next year."
He came to conclude that Mr Fraser was "really being driven to find an excuse to deny supply and defeat the budget".
If Sir John's letters to the Queen are discursive, updating her on conversations, personalities, tactics, and different ways the crisis might play out, the responses from Sir Martin are much more succinct. He encouraged Sir John, assuring him his stories were of great interest to the Queen, but he also made it clear the decisions were his to take.
While in late September 1975, Sir John believed there was bluff and brinksmanship on both sides, by October 17, he was telling the palace, "The country is set on a collision course now of historic proportions".
On October 20, Sir John described Mr Whitlam as in an "exuberant, even euphoric, mood", but hardened in his determination not to cave in. And he briefly made made light of the saga, describing it as "the local drama". "As with all such serials we must wait to see how the various political heroes manage next week. In the meantime I feel called upon, at this stage, to do nothing," he wrote.
But within a few days, he was again in crisis mode, writing on October 22, 23 and 24, saying he was under great pressure to act, and had tried to bring about a compromise, but neither was prepared to budge.
On October 27, Sir John wrote to the palace to say the crisis might come to a head by the end of November, when the government might well find itself attempting to govern without money, and he might have to consider dissolving the Parliament.
"I am remaining calm about it all and seek no 'man of destiny' role in all of this," he wrote.
On November 6, he tells the palace he had met Mr Fraser and Mr Whitlam, with Mr Fraser insisting he would go on denying supply as many times as Mr Whitlam attempted to send his budget bills to the Senate, and Mr Whitlam standing by his refusal to call an election. Public servants would be paid till the last pay period in November, Sir John wrote.
"The crisis is now a very serious one ... an important decision one way or the other may have to be made by me this month."
In a letter dated November 4, Sir Martin gave him a more detailed reply than previously, telling the governor-general that while it was often argued that the power of the crown to dissolve parliament no longer existed, "I do not believe this to be true".
"I think those powers do exist ... but to use them is a heavy responsibility and it is only at the very end when there is demonstrably no other course that they should be used," the Queen's secretary wrote.
"I am sure you are right in taking the line that your crisis has not yet crossed the threshold from the political to the constitutional arena.
"Mr Fraser wants to believe it is already a 'constitutional' crisis because he wants you to bring about an election which he thinks he can win. If the tide of public opinion continues to flood against him, he may well modify his view and look for a way of retreat."
He told Sir John he was impressed with his skill, wisdom and impartiality, and finished, with, "The fact that you have powers is recognised, but it is also clear that you will only use them in the last resort and then only for constitutional and not for political reasons."
On November 5, Sir Martin wrote again, telling Sir John the Queen wanted it worked out in Australia, and while "anything you may do could indirectly affect the monarchy in Australia", as long as he acted in accordance with the constitution, he could not damage the institution.
He finished with a quote from former Canadian prime minister Arthur Meihen, who said the role of the governor-general was to ensure responsible government was maintained, the government was responsible to parliament and the parliament was responsible to the people.
Whether that was taken by Sir John as a sign of approval of any move to sack the prime minister is not clear, but it was apparently the last word from the Queen before the November 11 dismissal.
On November 11, Sir John told the palace he had taken the decisive step and dismissed Mr Whitlam and appointed Mr Fraser.
Mr Whitlam had come to see him, telling him, "I shall have to get in touch with the Palace immediately."
"To this I replied that this would be useless as he was at that time no longer Prime Minister. I had already signed the document terminating his commission."
Sir John said he had made the decision without informing the Queen in advance because the responsibility rested with him and it was better for her not to know in advance She agreed, Sir Martin telling him he had acted "not only with perfect constitutional propriety but also with admirable consideration for Her Majesty's position."
Sir John wrestled with what he had done, unsure whether to resign, and hit with an avalanche of public opposition. He wrote to the Queen on November 20 to explain again why he had dismissed Mr Whitlam, telling Sir Martin that both leaders were "stubborn and proud men"and he had been concerned they "were on a collision course which, if maintained could cause enormous chaos and even political disaster". Mr Whitlam was on a crusade to "destroy the power of the Senate on money bills".