I was going to write a lengthy essay on this, but I risk being scooped by events, so here’s the short form. Paramilitaries are like unguided missiles, stoked to a fevered pitch by emotional appeals to patriotism. There is no “off switch.” Putin has to let their springs run down a bit, and even then, they are a huge problem.
So Kerry’s demand that Putin disarm the revolutionaries “within hours” is obvious theater. Kerry knows how it works.
Those who live to return to Russia have left the blood of their comrades in Ukraine. Just as with the Bay of Pigs Invasion, there are going to be some very angry people. They will accuse Putin for betrayal. Recall that some theories of the JFK assassination implicate Cuban counter-revolutionaries. Without any suggestion by me that such theories are valid, because I have no idea, this should give you an idea of how serious a problem it is.
It is somewhat encouraging that four OSCE monitors have just been released. This suggests that the paramilitaries are, in fact, coming off their surge, and becoming semi-manageable.
But the returning paramilitary is a ticking time bomb, with ample capacity for conspiracy directed at revenge. Putin is an expert at staying alive. If necessary, he will liquidate particularly dangerous individuals.