"can Putin afford to back down or will Mr Macho man challenge...

"can Putin afford to back down or will Mr Macho man challenge the west ?"

Why should he have to challenge the West? Really.
The Crimeans voted to be part of Russia....the Ukraineans are mixed, with some applying to join the Russian army....
The Crimean leader is not democratically elected....
Surely this is an internal issue , and not one needing Western intervention, which if it occurs, could become rather ugly.
I think the West should mind its own business and sit at least this one out.

GZ