He has backed away from his comments today. After being briefed by his generals on the provisions of the Hague Convention relating to cultural sites, he now says he will follow the law.
Must have been the usual shoot from the hip Trump bs. I don't believe that he was thinking of the idea that "cultural sites" may serve as shelter for military activities when he made the statement. I sort of disregarded it when he said it, just the usual bombast.
As to whether it is a good thing or not to consult with allies before making a move, that's always a judgement call. There's a price to pay either way.
I still haven't heard a good strategic reason for making the move. (I don't mean just from this conversation.) Is it part of longer term strategy? Are people making up the strategic value after the fact? There may be a group of foreign policy advisors who thought and planned over these things but that's not the impression I get from media, which may not mean much. OTOH, Trump has never given the impression of being a long-term strategic thinker, or at least he's hidden it well up to now. Unless you know what the long-term plan is, it's difficult to judge if this killing furthers that plan.
I recommend again that NPR Fresh Air podcast a few pages back about an analysis of the long-term strategy in Afghanistan (various failures in the Bush and Obama administrations), which suggests that there may not be good long-term planning at work in USA foreign policy circles. That is, recent history does not fill you with confidence. Some high-ranking officials involved in that arena came right out and said so. (For Russ's benefit, it was the officials who said so, including military ones, not the leftie NPR journalists.)
Might be useful to look at things from the other people's point of view. Eighteen not very effective years in Afghanistan in the sense of accomplishment with many people on the ground preferring the Taliban chieftains over the corrupt Afghan "government". Iraq's mess not exactly fixed or even on the way. So in the midst of that, the US kills some Iranian general. As retaliation of what happened at the embassy, it's maybe not a bad idea, but will the aftermath be good. I really like the Zen master story scene from near the end of the movie Charlie Wilson's War, (language caution)
https://www.youtube.com/watch?v=e2cjVhUrmII.
Btw, I thought that reference to Neville Chamberlain earlier was a cheap shot, although it was funny. It's not we're dealing with Hitler and no one was handing over the Sudetenland. Things are murkier than that.