Landing in England ?
The "actors" : Spain, French Foreign Minister Vergennes, comte de Broglie.
The idea of a landing is an old French one, very actively promoted until 1779 by ancient Minister Choiseul and its implementation has been carefully designed by the two (almost twins, they were born within one year) Broglie brothers, specially the younger one :
- Victor François, duc de Broglie, (17 octobre 1718 - 30 mars 1804, "Maréchal-général" (rarely attributed and meaning first maréchal de France)
He was the father of Victor de Broglie, (1756-1794 guillotined), who landed in the Delaware, with the son of maréchal de Ségur War Minister, with Lauzun sailing back to take soon the command of the remaining French forces in North America, and quite a few other distinguished members of the finest aristocracy (and founding members of the Cincinnati de France).
As early as 1760, his aide maréchal des logis was Jean de Kalb, serving therefore under the younger brother Charles de Broglie Ruffec. At the end of the Guerre de Sept Ans, Kalb is lieutenant-colonel.
- Charles François, comte de Broglie, marquis de Ruffec (20 août 1719 - 16 août 1781). The latter, and said to be the most gifted of the pair, was in charge of the "Secret du Roi" at Louis XV's time. An intelligence service, which was suppressed in 1774 by Louis XVI when he succeeded his grand father.
Broglie Ruffec was himself also a good general as he behaved very efficiently in the defence of Prague against Frédéric II.
He is also the one who organized the famous "Metz dinner" (August 8, 1775) when 18 years old La Fayette was convinced by the duke of Gloucester, George III's brother, of how the Insurgents' revolt was justified ! Comte de Broglie Ruffec suggested Choiseul to choose Kalb for an exploratory diplomatic (and secret) mission in North America (1767).
Later on, he (Broglie) was the one who organized, in conjunction with Beaumarchais, a great part of the supports to the American Revolution at its early stage. He nursed for a while the idea to serve as leader of the Insurgent' armies.
Comte de Broglie's subordinates have organized La Fayette's departure and paid for his vessel (whatever the legend says) and Kalb was missioned to coach La Fayette when the young man was balancing between obeying his family or sailing away.
Landing in the UK.
Comte de Broglie had drawn, as early as the 1760s, the very precise scheme of a landing in England (what organization, which chiefs and regiments, how many beefs, boats, etc, how to proceed when landed, ....).
On December 17, 1777, he sends to the King an updated scheme and suggested strategy. He was received to explain it in details. Regiments move towards the coasts. On May 11, 1778. His elder brother, Maréchal de Broglie was named to command the assembled forces in Britanny and Normandy, while Ruffec was sent …to Metz at the great sorrow of both ! The Normandy manœuvres to check the better tactics in a battle and Rochambeau's party proved the method promoted by duc de Broglie is not the most efficient. On Spring 1779, Maréchal de Broglie was replaced by comte de Vaux.
Vergennes writes to his ambassador to Spain, Montmorin : il s'agit "d'accréditer le dessein d'une expédition" mais en excluant "toute idée de débarquement et d'invasion". Abbé de Very writes in his journal Maurepas (Ministre d'Etat) told him about Maréchal de Broglie; "en tout cas, nous le bornerons alors à un commandement insignifiant, puisque nous ne voulons pas faire opérer l'armée….Ici, ce n'est qu'une vaine montre que nous voulons faire à l'Angleterre".
Vergennes again: : "Il ne faut pas se flatter de pouvoir la tenter [la descente] avec moins de 70 vaisseaux de ligne et 70.000 hommes d'effectifs de troupes, dont 10.000 de cavalerie. Si l'on considère ce que cela demanderait en bâtiments de transport, en artillerie, …. Il y a de quoi s'effrayer". … "Je pourrais annihiler l'Angleterre, que je m'en garderais comme de la plus grande extravagance".
In the mean time (August 1778), Floridablanca, Spain's ambassador to France, has presented Louis XVI a scheme similar to Charles de Broglie's : like Carthage by the Romans, England must be destructed at home. It is Spain's requisite to enter the war, take it or leave it. Vergennes tries to reorient the scheme towards Ireland where an insurrection against the British might be hoped for.
On June 20, Vergennes had written already to Montmorin (ambassador to Spain) : "comme il ne s'agit pas d'une destruction physique, de faire la conquête matérielle de l'Angleterre et de la réduire à la condition d'une province, n'arrivera-t-on pas au même but si l'on travaille seulement à l'affaiblir dans le plus haut degré où il sera possible d'atteindre?" and further: " [L'Angleterre] est nécessaire dans la balance de l'Europe, elle y tient une place considérable, ….".
Charles de Broglie, after loosing a stupid claim retires to Ruffec and dies a few month later. His detailed project has been considered by all military analysts ever since, beginning with Napoleon, as absolutely remarkable.
[Main source : Gilles Perrault "Le secret du Roi", Vol III "La revanche Américaine", Fayard 1996. Most of the quoted correspondences can be found in Archives étrangères de France, Espagne file.]