what does the word “declared “ mean in the relevant canons?
"They (Mexican Church leaders) did nothing new, surprising or arbitrary. They simply announced publicly what is contained in the law of the Church... which expresses our appreciation for life and that human individuality, human personality is present from the first moment (of life)".
Under Church law, someone who knowingly does or backs something which the Church considers a grave sin, such as abortion, inflicts what is known as "automatic excommunication" on themselves.".
making it crystal clear there is such a thing as automatic excommunication people bring on themselves. So, it really doesn't matter what declared means. Unless, of course, your argument is that Pope Benedict XVI was wrong and automatic excommunication isn't really the same as someone being excommunicated by formal declaration.
In 2007, now Pope Francis wrote, we should commit ourselves to Eucharistic coherence, that is, we should be conscious that people cannot receive holy communion and at the same time act or speak against the commandments, in particular when abortions, euthanasia, and other serious crimes against life and family are facilitated. This responsibility applies particularly to legislators, governors, and health professionals.
Both Benedict XVI and Pope Francis have described politicians, parliamentarians, and others who facilitate abortion in some way as an identifiable, distinct, class of persons in the eyes of the Church.
Both Pope Benedict XVI and Pope Francis say this entire class of persons meet the criteria to be excommunicated and have in fact already excommunicated themselves. This entire class of persons, then, ". . . are not to be admitted to holy communion", therefore it can be argued that this entire, identifiable, self-identifying, class of persons are all already under interdict.
Furthermore, what "declared" means is irrelevant because Canon 915 says, "Those upon whom the penalty of Excommunication or interdict have been imposed or declared and others who obstinately persist in manifest grave sin . . .", not only "those upon whom the penalty of excommunication has been declared . . .". No formal action on the part of the Church is needed when someone very publicly, ". . . does or backs something which the Church considers a grave sin . . .", especially when that person is a member of a clearly identified class of persons, a self-identified, voluntary, member of that clearly identified class of persons, very public persons at that, who the Church has identified as having automatically excommunicated themselves.
They are public persons, they go on record as obstinately persisting in manifest grave sin, they make public speeches advocating manifest grave sin, no formal declaration by the Church is required when someone publicly, very publicly, obviously declares them self excommunicated by the standard of Canon 915.
The only time what "declared" means mattered was when these individuals declared their own excommunication.