CAVET: as an extremely amateur historian-wannbe, my readings over the years have me coming to one overwhelming conclusion; The multiple American attempts at invading Canada would have well been successful, had it not been consistently the case, whereby those in command [on both sides of the border-lands] made tragically poor decisions. Time and time again, decisions by commanders of both high and low rank, resulted in victory and/or defeat. Poor leadership was oft married with corruption and malfeasance to determine the course of conflict. The Battle of The Plains of Abraham being one such outstanding example.
That I've previously read bits and pieces; it took the reading of many sources to piece together the tragedy that was the fall of Quebec City, surrounded by corruption, malfeasance, nepotism and incompetence. While there have been thousands of papers written on the strategic, tactical successes and blunders by both Wolf and Montcalm, I found the following intriguing.
Part 1: The Battle of The Plains of Abraham (Quebec City)
Rigaud de Vaudreuil de Cavagnial, Governor General of New France (Canada);
François Bigot Intendant of New France. This guy controlled the money in New France. Theoretically he was subordinate to and worked for Vaudreuil. In practice Bigot controlled what can best be decribed as an earlier version of the Italian mafioso.
General Louis-Joseph de Montcalm-Gozon, Commander of the forces in New France during the Seven Years' War . Montcalm was subordinate to Vaudreuil.
General Wolf was the military British guy...in charge. On the other side.
Louis Du Pont Duchambon de Vergor was a junior French military officer during the Seven Years' War. Subordinate to Montcalm, de Vergor had many friends in very high places; most notably, François Bigot.
And so the story begins.
Initial incompetence is allowed to breed future disaster:
In 1754, de Vergor was named as commander of France's Fort Beauséjour in what would eventually become New Brunswick. On June 4, 1755, Fort Beauséjour was attacked by a force led by Robert Monckton.
After a few days of siege, a cannon ball exploded inside the fort, killing six officers and several soldiers. Vigor panicked, and raised the white flag. The British gave him favorable conditions, and gave permission to him and his men to go to Louisbourg. de Vergor was tried by court-martial at Quebec City in September 1757 and acquitted of charges that the forts were not adequately defended, and allowed to continue his service as an officer.
Two years later...
The Battle of The Plains of Abraham (Quebec City)
de Vergor [no Captain] was a part of the defense of Quebec under Louis-Joseph de Montcalm during the siege prior to the Battle of the Plains of Abraham.
On the night of September 12, 1759, Vergor was in command of a small encampment (Fulon Post, present day 'Wolf's Cove') tasked to guard the upper portion of a rough trail leading from the St Lawrence River up to the plains; As de Vergor slept, his command was the first to contact the British under General James Wolfe. [1.]
With great irony, the British officer in charge of the initial assault force was again Robert Monckton [now Major]. Remembering his encounter at Fort Beauséjour with de Vergor four years previously, it must have came as a great comfort knowing that de Vergor was now in command of Fulon Post.
A second accounting:
Wolfe's Cove, formerly the Anse au Foulon: A mile and a half above the city [up river] of Quebec City. In 1759 the French 'Fulon Post', was commanded by de Vergor. Early on the morning of September 13th 1759 Wolfe landed with his army at the foot of the cliffs; a small party of volunteers climbed the steep path, surprised and overpowered de Vergor's handful of men; the army followed - "In the gray of the morning the long file of red-coated soldiers moved quickly upward, and formed in order on the plateau above;" the first step had been successfully taken in the movement that led to the Battle of the Plains and the cession of Canada to Great Britain. Bib.: Parkman, Montcalm and Wolfe; Casgrain, Wolfe, Montcalm. 
What was not revealed in references 1 or 2, was the fact that de Vergor had previously unilaterally released 50% of his troops, to depart home, to tend to their fields; the deal was that they had to work 'his' land holdings as well.[3.]
This left Fulon Post at most at 50% strength and likely at far less than that.
In historical terms, this was to be the second time that de Vergor's reticent incompetence had failed his country on an increasingly massive scale.
Tellingly, Montcalm had become increasingly concerned with the exposure of the Fullon Post and the plains, requested of Vaudreuil, that de Vergor be replaced [based on his historical record of leadership performance (or lack thereof)]. Vaudreuil denied the request. It must be acknowledged that a nepotistic relationship between de Vergor [who was one of ' Bigot's Gang '] and Vaudreuil existed and is presumed to have played a part in de Vegor's protection. With tragic results.
Part 2 - Where were the Guns ?
The second tragedy in the subsequent battle for Quebec was that when Montcalm requested all of the twenty-five guns [horse drawn artillery] available for deployment, Vaudreuil only released three; against the single (one) field piece that Wolf’s artillerymen had managed to disassemble and drag up the escarpment.
Apparently, whilst the remaining guns were fully serviceable and located at Beaufort Works, Francois Bigot the Intendant of New France had rented the artillery unit's horses out, for his personal profit and thus they were not available to be harnessed in front of the guns and moved with all speed west of Quebec City. [4.]
Horses were apparently in very short supply to everyone's individual and collective wonderment. Thus Montcalm was severely limited in his battle plans for the defense of Quebec City on the Plains of Abraham, regarding the movement of guns, ammunition, troops and supply's in general.
The drama of Quebec ended with the two principals Montcalm and Wolf dead.
Vaudreuil along with Bigot and twenty other officials were tried in France for the loss of French possessions in North America. They were sent to the infamous French prison, Bastille, where they stayed for a year before being brought to trial for fraud. They spent another two years awaiting judgment.
The trial in France into the loss of the empire in North America lasted 15 months.
Vaudreuil put up a spirited defense. He maintained he was solely preoccupied with military matters and had nothing to do with finance. He said the sordid charges against him insulted his noble lineage and the honor of the armies of France. He wrapped himself in the mantle of Montcalm and appeared in court as a soldier of France, innocent and ignorant of the conniving and corruption that swirled about him. He was acquitted, awarded the Grand Cross of St. Louis and given a pension of 12,000 livres. He retired to his family chateau where he died at the age of 80 in 1778. [5.]
At the trial of Bigot his defense filled some 1000 pages. Despite this he was found guilty. The prosecutor demanded that he be made to kneel before the main gate wearing only a shirt, a rope around his neck and a placard labeling him "Thief." He was then to confess his crimes and have his head chopped off. The court decided instead to confiscate all his possessions, fine him 1,500,000 livres and banish him from France for life. He paid the fine and went to Switzerland where he "successfully fitted himself into local circles" and led a comfortable life before dying on January 12th, 1778.
de Vergor, eventually made his way back to France, wed, bore two children and faded into obscurity.
Tragically wrote one historian, there was enough ability among them [save de Vergor] to have defended New France from ruin. Torn from without by invasion and from within by pillage and dissension, there was no way the colony could survive. [5.]
2. Lawrence J. BURPEE, The Oxford Encyclopaedia of Canadian History, London and Toronto, Oxford University Press, 1926, 699p., p. 692.
3. William Wood, The Plains of Abraham, in The Passing of New France. A Chronicle of Montcalm, Totonto, Glascow, Brook & Company, 1915, 149p., pp. 12-142
4. Century of Conflict – Vol 2 of 6, The Struggle between the French & British in Colonial America 1956, by Joseph Lister Rutledge, Doubleday p. 497