With many of his regulars sent to New York, Carleton was facing a scarcity by the time of the invasion. He had little success recruiting the provincials for a militia, so he only had the local Native Americans to turn to, who wanted to fight. The Crown also pressured him to do so but he refused out of fear that they would kill noncombatants.
So what would happen if he did choose to recruit them? How would this effect the invasion and would they really go around killing noncombatants? What effect would the latter have?
It was my understanding that he was successful at recruitment among the Quebecois. OTOH, some 500 Anglo-Canadians ran off to join the Americans.

Apparently, the mostly Calvinist (if I can call them that) Yankees were filled with promises to the Anglo-Canadians of what would be done to the French-Canadians. Promising total primacy to English-speakers, and second-class status for the French-speakers.


This certainly wasn't policy per se from the Continental Congress or Washington, but there appears to have been anti-catholic scuttlebutt in the camps of the Americans, and that fact got out.
As to his failures to defend Montreal and Ft. St.John, it was impossible. He had neither the forces needed nor the assurance of timely re-inforcement should the Americans be reinforced-which in fact they were. Had Carleton been slugging it out up at Montreal (which was mostly defenseless after the siege of Fort St. John ended) and Arnold then took Quebec City from the rear, Carleton would have seen his army starved and destroyed, while he would have eventually been court-martialed.
As it was, he skillfully played a defensive campaign, always being certain that Quebec City (town, really) was never in serious danger of capture, so when the ice melted in the Spring overwhelming British reinforcements arrived and destroyed the American invaders.
After this, and all he did to aid the American Loyalists, small wonder that Carleton was the only British flag officer to emerge from the American Revolutionary War with his career significantly
enhanced. And with the huge influx of English-speaking American Loyalist refugees, Anglo-Canadian opinions of Carleton did a complete 180 degree turn.
