ita enim causa CONSTITUITUR, provinciam Siciliam virtute istius et vigilantia singulari dubiis formidolosisque temporibus a fugitivis atque a belli periculis tutam esse servatam. = For his cause is stated in this way; that by his valour, and by his singular vigilance exerted at a critical and perilous time, the province of Sicily was preserved in safety from fugitive slaves, and from the dangers of war.
Here, CONSTITUITUR is passive, and the last clause is obviously an acc + inf
But how can a passive verb take a direct object? It seems strange to me
To my mind there are two possible readings of this, either we imagine that there is an implied verb of speaking — “His case is presented thus; [he said that] the province of Sicily etc”; or else, that the entire accusative clause is functioning as a clarification of the ‘sic’, and so taking the role of a single grammatical expression. His case is presented thus; [that is], the province of Sicily etc."
I also thought that the sentence has ellipsis of the verb like “dixit”, but I was not sure. I just linked the accusative clause with the verb Constituitur