I found this interesting quote from celebritytypes.com/quotes/thomas-jefferson.php
On the downfall of the French monarchy
Jefferson: "And here again was lost another precious occasion of sparing to France the crimes and cruelties thro' which she has since passed. … The king was now become a passive machine in the hands of the National assembly, and had he been left to himself, he would have willingly acquiesced in whatever they should devise as best for the nation. A wise constitution would have been formed, hereditary in his line, himself placed at its head, with powers so large as to enable him to do all the good of his station, and so limited as to restrain him from its abuse. This he would have faithfully administered, and more than this I do not believe he ever wished.
But he had a Queen of absolute sway over his weak mind, and timid virtue; and of a character the reverse of his in all points. This angel, as gaudily painted in the rhapsodies of the Rhetor Burke, with some smartness of fancy, but no sound sense was proud, disdainful of restraint, indignant at all obstacles to her will, eager in the pursuit of pleasure, and firm enough to hold to her desires, or perish in their wreck. Her inordinate gambling and dissipations, with those of the Count d'Artois and others of her clique, had been a sensible item in the exhaustion of the treasury, which called into action the reforming hand of the nation; and her opposition to it her inflexible perverseness, and dauntless spirit, led herself to the Guillotine, and drew the king on with her, and plunged the world into crimes and calamities which will forever stain the pages of modern history.
I have ever believed that had there been no queen, there would have been no revolution. No force would have been provoked nor exercised. The king would have gone hand in hand with the wisdom of his sounder counsellors, who, guided by the increased lights of the age, wished only, with the same pace, to advance the principles of their social institution.
The deed which closed the mortal course of these sovereigns, I shall neither approve nor condemn. I am not prepared to say that the first magistrate of a nation cannot commit treason against his country, or is unamenable to its punishment: nor yet that where there is no written law, no regulated tribunal, there is not a law in our hearts, and a power in our hands, given for righteous employment in maintaining right, and redressing wrong.
Of those who judged the king, many thought him wilfully criminal, many that his existence would keep the nation in perpetual conflict with the horde of kings, who would war against a regeneration which might come home to themselves, and that it were better that one should die than all. I should not have voted with this portion of the legislature. I should have shut up the Queen in a Convent, putting harm out of her power, and placed the king in his station, investing him with limited powers, which I verily believe he would have honestly exercised, according to the measure of his understanding. In this way no void would have been created, courting the usurpation of a military adventurer, nor occasion given for those enormities which demoralized the nations of the world, and destroyed, and is yet to destroy millions and millions of its inhabitants.
There are three epochs in history signalized by the total extinction of national morality. The first was of the successors of Alexander, not omitting himself. The next the successors of the first Caesar, the third our own age. This was begun by the partition of Poland, followed by that of the treaty of Pilnitz; next the conflagration of Copenhagen; then the enormities of Bonaparte partitioning the earth at his will, and devastating it with fire and sword; now the conspiracy of kings, the successors of Bonaparte, blasphemously calling themselves the Holy Alliance, and treading in the footsteps of their incarcerated leader, not yet indeed usurping the government of other nations avowedly and in detail, but controlling by their armies the forms in which they will permit them to be governed; and reserving in petto the order and extent of the usurpations further meditated. But I will return from a digression, anticipated too in time, into which I have been led by reflection on the criminal passions which refused to the world a favorable occasion of saving it from the afflictions it has since suffered."