faith, or the capacity for faith?

[Ruskin, writing to Charles Eliot Norton, 27 December 1872, responding to a manuscript on Sienese history Norton had sent him:]

I was greatly surprised by the early dates you assign, and prove, for the fall of Siena and also, by your ascribing it in the end, so completely to the failure of religious faith.

Q. and this is the only thing which – during the whole day I wanted my pen to suggest – all the rest being unquestionable and as perfect as work can be – should we not rather say, – the failure of the qualities which render religious faith possible, – and which, if it be taught – make it acceptable?

How far religion made – how far destroyed – the Italians is now a quite hopelessly difficult question with me. My work will only be to give materials for its solution.