One of the alarming effects of living in a society less and less beholden to traditional Christian morality is that many Catholics find themselves in situations where they are closely associated with practices they find abhorrent. Taxes go to fund abortions, the stores we patronise sell pornographic magazines or books, teachers are required to teach an “inclusive” view of marriage, and so on.

In navigating this minefield, there are some fairly well-established tools that we ought to have in our ethical toolbox, from the theological tradition on the subject of “cooperation with evil”. This is when a person, doing something good in itself, has his or her activity hijacked by another who uses it to do evil.