I live in the United States and the government here routinely spends money to wage wars around the world. Cost is not a consideration if the ends are achieved.
If the intent is purely to cause chaos and doubt they could achieve this.
I dont think it would happen, but curious what people think they would do.
For me I would certainly want more block confirmations until the cause/culprit(s) identified. I would also consider it an attack if it was shadow mined and wouldnt be opposed to marking their block as invalid.