Could a 1939 war reshape Soviet and Polish choices?

Would the Soviet Union or Poland join a British-led alliance against Japan in 1939?

Soviet alignment is likely because fighting with Japan had already begun, while Poland's position remains precarious and contingent.

Soviet involvement is plausible because the USSR was already fighting Japan in 1939. A visibly united Allied role in the Spanish Civil War could draw Germany and Italy into prestige contributions while making further adventurism harder to sustain. Hitler and Mussolini might also find enough political glory in those operations to delay another crisis. Germany's poor logistics would make it difficult to maintain a valuable expeditionary presence and attack Poland at the same time. Poland remains the uncertain partner, but even a small destroyer contribution could change alliance politics and generate favourable coverage in the United States.