hi clo,
i'm not sure that is always true. but i know the us perceives it that way.
take the libyan conflict. the us wasn't the prime mover (britain and france pushed for western involvement) and didn't join in the air campaign.
but iraq was mostly a us adventure, ignoring good advice from france, germany, russia and china.
afghanistan involved most everyone you'd expect.
i agree that the us has far the strongest military and usually leads.
but the point i'm making is that in this case, russia seems to be pushing for a more sensible, non-military solution. so let's all back them. the us has a bad idea so let's not pursue it.