We too have interests in this...a staunbch ally who readily answered our call for military help, a strategic tie into the Caspian region and the Stan states, oil from those regions.
If we do not act, as I said, no one will, and we will also be the worse for it...and the opening move in Putins re-establishment of the block states will go un-opposed and he will proceed with his next moves emboldened.