>>The only thing possible is to “express fears” of escalation.

And to limit the range of the weapons systems provided. At this point, I think the Russians might already know how untenable their hold on Crimea is once the Kerch Strait bridge is impassable to heavy trains. At that point everything has to come via truck over the 'land bridge' of occupied Ukrainian territory. Those territories have been supplied via Crimea - and the bridge. I expect one of the reasons for their recent withdrawal from Kherson has to do with logistics issues coming from the railroad portion of the bridge being unsafe for heavy trains (fuel train set afire when the road spans were dropped - catching that train argues for set charges, but that's a different discussion).

As far as listening to "the advice of moderation" , the Ukrainians are in a struggle for their very existence as a people. Even so, are they shelling any pre-2014 Russian territory?