[pantalaimon]

I think for many Putin actually invading Ukraine was simply unthinkable.

Sure, some saber rattling and destabilization, but outright war?

US intelligence was not always credible, so when they presented facts that conveniently benefited American interests (shale gas export), people were sceptic.

That allowed Putin to prepare an invasion in plain sight.

[markus_zhang]

State invades other states and I don't know why it is unthinkable. All major powers already know about the plan at least vaguely beforehand.

[s1artibartfast]

Perhaps everyone thought Russia was Saber rattling in January when they gave a 1 week deadline to NATO saying they would invade if they didn't receive it.

That said, following Russia demand, the US president went national TV and announced that Russia will likely invade Ukraine and the US will not go in.