So many Qs!! Are you like 5 years old expecting me to answer you?!
If NATO didn't keep on expanding toward Russian borders, then nothing would have happened, but the US in the words of their own ex-leaders, is the biggest destabilising country on this planet, hence the result and the hell which is about to be unleashed unless something is done sharpish. But hey, you being hardcore blind patriots of the US would never admit to being at fault.
i sense a certain level of aggression and frustration on your side ...
that's great!
now - drive to moscow -
go to the red square and SHOUT IT ALL OUT !!!
and take a big banner with you and write something on it, like maybe:
PUTIN IS A TINY SON OF A BITCH
AND MEDVEDEV IS HIS COCKSUCKER
...
have fun!!
(... then come back here and tell us, how it went).