In Brazil we have a famous saying, not related to wars but football, "já combinou com os Russos?" or in literal translation, "Did you already check with the Russians?".
A very famous player - Garrincha, arguably one of the greatest players of early football/soccer - listened to his explanation and asked
"That's very cool and all, Mr. Feola. But have you checked with the Russians?"
(In English I think 'did the Russians agree' may sound more idiomatic)
[1] https://barrichelo.com.br/teoriadosjogos/list-trechosimprime...
It also doesn't fit very well, because it's more intended to be used about cartoonish plans that expect other people to behave exactly as the plan predicts. I dunno why the GP got to it.