It seems really interesting, that the obvious example is simply the Law of Change.
The world was changing outside of Tibet, and the Tibetan's simply didn't want to accept the reality of it.
The same thing happened to Japan, when they stayed isolated for too long.
Eventually, being cut off, they blinded themselves to the fact that military technology was advancing elsewhere, and that meant that their neighbor nations suddenly (it seemed) had the ability to invade them and take what they wanted, (or in the case of japan, force treaties that the Japanese didn't like, as in the Meiji era).
When, in reality, it wasn't a sudden change at all, it happened over time, naturally, but by being so cut off from the rest of the world, they blinded (deluded) themselves to the reality of it.
Destruction was a natural consequence of that. They were no longer strong enough to defend themselves against external threats.
Essentially they were fighting, or ignoring the natural Law of Change.
The 13'th Dalai Lama saw this, and tried desperately to get his country to modernize, with no effect, and in vain. The powers that be, in his country at the time simply didn't want to face external realities of the changing world around them.
It was fear of change, and the unknown that that brings, and clinging to the status quo, plain and simple. (the cause of suffering is clinging rooted in ignorance)
Change, and constant change is a basic Buddhist teaching.
Trying to keep things the same when things are changing is delusion.
The Tibetan leaders were simply deluded, and a few, like the 13'th Dalai Lama, were trying to point that out to them.
They willfully refused to listen, and acknowledge and act regarding the changing world around them, and they got the consequences.
It's really that simple.
"Life is full of suffering. AND Life is full of the Eternal
IT IS OUR CHOICE
We can stand in our shadow, and wallow in the darkness,
We can turn around.
It is OUR choice." -Rev. Basil
" ...out of fear, even the good harm one another. " -Rev. Dazui MacPhillamy