The following is an excerpt of a letter from Marie-Antoinette to her mother Empress Maria Theresa, written on February 17, 1777. Marie-Antoinette was twenty-one years old and had been Queen of France for almost three years. It demonstrates that in spite of the popular perception of being a nitwit, the young Queen had an awareness of the political situation in Europe. At the time the letter was written, Marie-Antoinette was at the height of the partying phase of her life, and not actively engaged in political affairs; Louis XVI encouraged her not to become involved. He knew that his Queen, as an Austrian Archduchess, was pressured by her family to influence him to undertake policies favorable to Austrian interests. He tried to keep her from meddling by isolating her at Petit Trianon, surrounding her by a circle of friends (the Polignacs) who owed everything to himself. That she had a basic sense of what was going on, long before the Revolution when she played a larger role in the political scene, shows that she had inherited some of her mother's astuteness.
When she says that "it would be the greatest good fortune if these two sovereigns [her husband and her brother Joseph]...could trust each other" she is referring primarily to the fact that Louis did not trust the Emperor and would not go along with his plans. She was also acutely aware of the intrigues of the court and accurately predicted that the appointment of Cardinal Prince Louis de Rohan as Grand Almoner would bring "many intrigues;" it certainly brought about the Diamond Necklace fiasco.
Although I have very little experience of politics, I cannot help being worried about what is happening everywhere in Europe. It would be very terrible if the Turks and the Russians went back to war. At least here I am very sure they want to keep the peace. If my brother had come, I think, like my dear Mama, that his acquaintance with the King would have been very useful for the general good and quiet. It would be the greatest good fortune if these two sovereigns, who are so close to me, could trust each other, they could settle many things together and would be protected from the lack of skill and the personal interests of their ministers.
The Grand Almoner is at death's door; Prince Louis [de Rohan] will replace him in that office. I am really annoyed by this, and it will be much against his own inclination that the King will appoint him; but two years ago he allowed himself to be surprised by M. de Soubise and Mme de Marsan into a half promise, which they converted into a full one by thanking him, and which they have just now used to the full. If he [Rohan] behaves as he always did, we will have many intrigues.
(~from Secrets of Marie Antoinette: A Collection of Letters, edited by Olivier Bernier. New York: Fromm International, 1986, pp. 211-212)