Why did MacNally become an informer?

It certainly was not economically advantageous for MacNally to inform. The pension he received from the government was obviously so meagre that it forced his family into penury after he died and led to the eventual disclosure of his role as informer. With the broad legal experience that he had and the two legal textbooks to his name, could he not have forsaken radical politics and established a successful legal career? Was it principle that drove MacNally to inform? Did he perhaps see what he was doing as a means of preserving peace in the country? Or did he perhaps see his true loyalty as being to Dublin Castle? It hardly needs to be said, however, that MacNally’s actions rather show him to have been an unprincipled scoundrel, disloyal to the confidences expressed to him. It is more likely that once MacNally had sold himself for a mess of pottage he was unable to extricate himself from the dirty business into which he had got himself. Presumably the threat of being exposed by the government and thus ‘consigned to Moiley’ (i.e. killed) forced MacNally to continue as an informer. Or maybe he enjoyed an Iago-like fascination with danger and treachery? We will never know. Whatever his motivation, MacNally might have gotten away with it if, after his death, his widow had not sought continuance of his pension.