While acknowledging risks of escalation, it is not clear how to define a boundary. I heard someone saying: “I am tired of Russians defining what is ‘offensive'”. Why is sending them stingers ok, but planes – not OK? Why is shooting missiles from Russia to Ukraine – ok, and from Poland to Ukraine – not OK? Russians are now saying that supplying weapons is also not OK (and bombed near the Polish border).
We can do something small first, like send a humanitarian convoy to one of the surrounded cities by land or even by sea and have it protected by force that can shoot in self-defense.