He served as coadjutor to Bishop John England, who was busied with the vast jurisdiction of the diocese and his work as papal legate to Haiti.
A personal reluctance also factored into his delay: "If there is any other place where the knowledge of philosophy and theology and the faculty of preaching in English would rebound to the glory of God [let me go there].
In 1837, a Protestant lady brought to Clancy's attention a passage in The Crayon Miscellany, and questioned whether it accurately reflected Catholic teaching or practice.
It is an indulgence granted to them for a certain number of months, in which a plenary pardon is assured in advance for all kinds of crimes, among which, several of the most gross and sensual are specifically mentioned, and the weaknesses of the flesh to which they were prone.
Upon inspection, Clancy discovered that the document was not any sort of indulgence issued to the friars from any ecclesiastical authority, but a pardon given by the king to some parties suspected of having broken "forest laws".