There's an interesting long-form article today about the build-up to Russia's invasion of Ukraine in 2022:
The main thing that stands out is how in denial governments were that Putin would actually do this. Makes one wonder if they are similarly in denial about Trump's intentions?
"For many, the key intelligence lesson from Ukraine was stark: do not rule things out, just because they might once have seemed impossible."
(Also interesting how deluded Putin was in assessing the military reality. He had no idea how weak Russian forces were or how strongly Ukrainians would resist him.)