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?